There is only a small subset that seems to just be bigoted. And, yes, they do exist. I am pretty sure they are low in number. Most of the complaints are about things like body shops but there have even been complaints involving Disney.
Maybe I'm wrong, but if you can train your replacement, we probably didn't need a replacement. It's not like they move them up the ladder. They lay them off and pay the people with visas very little money, comparatively.
I don't have a dog in this fight, but I think, if true, they have a legitimate complaint. Most of them seem to agree that it should be bringing in experts and not lower paid people that need to be trained by the people they are replacing.
So, what do you think? Would you agree that there are legitimate concerns? Many of these complaints do not, to me, appear xenophobic or racist.