> The problem there isn't immigration, it's exploitation of workers.

Which is made easier by immigration. In addition to the simple law of supply & demand, it also impedes unionization:

Whole Foods' heat map says lower rates of racial diversity increase unionization risks - https://www.businessinsider.com/whole-foods-tracks-unionizat...

Amusingly, the ComputerWeekly article (citing the Business Insider article) omits the direction in which diversity affects unionization risk [1], while the two wikipedia articles (again citing the same Business Insider article) [2,3] strongly imply that diversity increases unionization, so the opposite of what their source is saying!

[1] These “risk scores” are calculated from over two dozen metrics – including employee “loyalty”, turnover, racial diversity, “tipline” calls to human resources and proximity to a union office – and shows the likelihood of employees in that location forming or joining a union. - https://www.computerweekly.com/news/252481961/Amazons-Whole-...

[2] Factors including racial diversity, proximity to other unions, poverty levels in the surrounding community, and calls to the NLRB were named as contributors to "unionization risk." - https://en.wikipedia.org/wiki/Criticism_of_Amazon#Opposition...

[3] Factors including racial diversity, proximity to other unions, poverty levels in the surrounding community and calls to the National Labor Relations Board were named as contributors to "unionization risk". - https://en.wikipedia.org/wiki/Amazon_and_trade_unions

Not really, labor laws in most places are the bare minimum acceptable. In Latvia, they are now hiring Indian truck drivers to compress even more the salaries.

Given that Latvian truck drivers are already the cheapest of the EU, you can figure out that legal is not the problem.