Mozza
It’s Carrick you know
First it's about skilled work, and minimum wage isn't relevant for that. Secondly, it's organized through chains of subcontractors and job agencies that do the housing to, it's extremely difficult to check and enforce even minimum wage. The builders don't know their rights, don't speak the language to find out and for their cost of living at home it's a lot of money anyway. The EU doesn't allow checks and enforcement that might be to the disadvantage of a foreign worker in any way. Thirdly doesn't allow favoring companies with local workforce (you don't know much about the EU, do you?).
So yes, the EU forces the cost of unemployment on the member state and prevents it from fighting unemployment effectively. It's a massive force for lower costs of labour, they're organizing a race to the bottom.
The EU shouldn't allow checks that would discriminate against foreign workers. The law must apply to everyone equally. It's up to the separate nations to design laws that stop the exploitation of workers.