Overworking H1Bs isn't what people are concerned about (yes it's an issue and part of the problem because it's an extra incentive). Importing people to supplant the local talent who are more than capable of doing the work, widening the labor pool to weaken labor's power, claiming it's "meritocracy" and that everyone who doesn't agree is somehow racist or "illiberal" are the core issues.

Nailed it.