That's not an excuse to allow the wanton exploitation of migrant labor that does, whether you want to admit it or not, undercut US labor on the margins. Not to mention the tolerance of labor violations against undocumented workers undoubtedly trickles up to legal labor and harms a lot more workers than just the migrants.

Illegal border crossings are a serious problem and the proper solution is not to hand wave away conservative concerns about it. All that does is maintain the status quo wherein migrant laborers are kept in legal limbo, facilitating their continued exploitation. That's bourgeois shit and if I wanted to get a little conspiratorial about it, I'd suggest that maybe that's the whole point of the "Americans don't want to do those jobs" rhetoric.

The proper solution is to legalize the migrants, get them documented, and protect them with US minimum wage and labor laws.