You get a nasty taste in your mouth when you watch workers - some of them presumably trade union members, some even claiming to be socialists - protesting against other workers just because of where they come from.
From a real socialist point of view the whole of the protestors argument suffers from (at least) three seriously bad assumptions.
First, it falls for the capitalist lie that bosses create jobs and give them out to workers. The whole entrepreneur myth. If you believe it you end up thinking that there is a limited supply of jobs and that workers have to go cap in hand to bosses to get them. But that is not the case. Workers create jobs, not bosses. (*)
Second, it allows the employers to divide and rule. By confusing two different arguments the local workers and the foreign workers are placed in a false opposition. Once again we let them drive a wedge between us. Once again we are manouvred into trying to improve our own conditions at each others expense.
One argument is about pay and conditions of the contract workers. Basically "should trade unions be able to force companies (including ones their members don't work for) to have particular conditions of employment?" (presumably regardless of where their employees come from) (**) The other is about allowing people to migrate for work at all. They are two different questions. "Should the government pass laws to stop foreigners coming to work in Britain?" This confusion surely suits the employers. (***) On the first one all the workers share the same interests - and they are opposed to the interests of the employers. On the second the short-term interests of the workers might seem to be opposed to each other (though I think the long-term ones aren't) (****) So the protestors place themselves in opposition to the contract workers. What they ought to have been doing (were they socialists) is trying to work with them, trying to improve pay and conditions in the job whoever is doing it.
Third, discriminating against workers based on where they live shifts the balance of power in industry even further way from workers and towards employers. If we allow them to reject workers from Italy or Portugal, where do we stop? British jobs for British workers! Piss off you paddies! English jobs for English workers! Sod the Scots! Lincolnshire jobs for Lincolnshire workers! Hull shite go home! Grimsby jobs for Grimsby workers! Immingham Lane jobs for Immingham Lane workers! Its crap. You would end up back at the feudal system with workers bound to jobs for life.
Allowing big business and the state (who are almost always hand in hand) to direct workers here and there at their whim, saying who can work in what place is not socialist. It is a retrograde step. Ideally anyone would be free to live and work anywhere. And the more people can move for work the less power the bosses have to dictate conditions. Workers who are trapped into working for one employer or in one place can be much more easily controlled and bullied and deprived of fair reward for their labour. We've known that since the Black Death.
If we bring back internal boundaries to free movement in Europe it will, in the long run, weaken the bargaining power of workers. Because capital will move where it wants whatever the laws say (and the laws are mostly written and administered by friends of capital anyway). Freedom of movement (besides being a good in itself, and a right we should allow no-one to take from us) is also the freedom, in the extreme, to say "take your job and stuff it". If workers are tied to their jobs, if there is only one or two or a handful of places where you can get work, then you do not have that freedom. And it won't improve wages because business will simply move to where the low wages are.
We shouldn't be under any illusion that these contractor companies are in business to promote the freedom of their workers - they are just trying to get as much work out of them for as little pay as possible. In order to do that they would very much like to control where and when the workers work,. It is to their advantage to have a couple of hundred isolated men stuck on a "floating hotel" (*****) with little or no contact with the other workers on shore. They probably don't pay as much for Portuguese workers as they might have to have to for British workers (after all wages in general in Portugal are lower than in Britain). And the isolation must make it easier for them to tell the workers what they want them to hear.
The thing to fight for is the pay and conditions of all the workers. Not squabbling about where the workers come from.
And the proper socialist way to do that is for the local and foreign workers to organise themselves in co-operation with each other, not to be duped into seeing other workers as their enemies.
(*) Workers create jobs, not bosses. Work makes more work. The more that is produced, the more that is consumed, the more that is bought and sold, the more there is to do. And innovation is a kind of work, not a kind of capital.
(**) If we wanted to be able to specify wages and conditions to employers bidding for contracts, and still follow EU law maybe the government should have signed up to the so-called "Social Chapter". Remember that? France and Germany wanted the kind of thing the protestors say they want - it was the British who opposed it. (AFAIR we have since agreed to a rather watered-down version of it) Or maybe we should not have made sympathy strikes and secondary picketing illegal, which the Tories did and which the Labour government has consistently refused to undo.
(***) It suits lots of people to obfuscate the two questions. It suits the employers because they can distract attention from pay and conditions and just talk about how they are following the rules. And because it enables them to present themselves as defending their workers against the nasty racist British yobs (how do you think this plays in Italy or Portugal?) And because they can divide workers against each other.
It suits the protestors (and some trade union officials) because they can blow emotional dogwhistles to try to get support from the Daily Mail readers and borderline fascists but if anyone accuses them of racism or nationalism or xenophobia they can take refuge in pretending they are only concerned about pay and conditions. And they don't have to come clean and point out that even if they "won" this time the contractors could easily replace low-paid Portuguese workers with higher-paid Portuguese workers.
It suits the right-wing shit-stirrers (and there are a lot of right-wing shit-stirrers getting involved in this) because they can point out the (real) hypocrisy of the Labour Party and some Trade Union leaders and they can carry on their usual tactic of exaggerating and stirring up racism (which is also real but nowhere near as prevalent as they want to make out)
It suits the racist, xenophobic euroseptic whingers because they can blame the EU (even though this is the result of the EU adopting British rules!) And yes there may well be a principled Socialist opposition to the EU rules on freedom of movement that is not infected by nationalism, racism, or xenophobia (which are different facets of the same thing) But if there is I haven't seem it yet. And I certainly haven't seen a non-socialist Euro-skeptic position that isn't riddled with petty nationalism.
(****) And its all based on making false categories. Yes the short-term interests of a British man looking for a job who can't get one conflict with those of an Italian who has already got a job. But they also conflict with those of his British neighbour who has a job. The economic reality of the situation (not enough money to go round in hard times) and the political reality (that it is the employers who control who is allowed to work and who not) are the same whether the workers are from Portugal or Portslade. Concentrating on the national origins of the contracto workers just makes it easy for the ruling class to drive a wedge between sections of the working class.
(*****) "Floating hotel" is the phrase they used on the TV news. They could just as easily have called it a "construction shack" or "work camp" or "barracks" or "dormitory". Each word has very different connotations.
(******) Keeping them in the floating barracks is probably a lot cheaper than employing men who travel to Britain independently and find their own accommodation. And the isolation must make it easier for them to tell the workers what they want them to hear. The old-fashioned divide and rule again.