For one, I don't think just because you can exploit entire groups of people you are right to do that. The market could command lower wages for <underprivileged group> and it would not be right. It just happens overseas employees are protected by no one.

What I find more interesting though, is that remote first companies behave the same. way E.g. look at GitLab salary calculator[0]. How does that make sense assuming a rational market?

[0] https://about.gitlab.com/jobs/developer/