*I absolutely agree with everything you've just said but these are common trophes, politics works like this all the time.
Personally, I think that's about making sure that people don't ask to many questions about the way the economic system works - who wins and who loses. Divide and conquer.*
Economic downturn is frequently linked to the rise of fascism. For a more recent (and possibly less reflexively emotive comparison), there's the Golden Dawn movement in Greece. That was somewhat stemmed by the anti-austerity coalition that then took power, but during the worst of Greece's austerity measures, their version of the National Front was most definitely on the rise. This is an observable pattern throughout history. The normalisation of these types of arguments as "just how politics works" is part of that pattern.
A minority group is scapegoated as the reason for economic downturn, then dehumanised so that the erosion of that group's rights does not cause mass outrage. The underlying motivation may simply be to pacify the masses, but they've done it by creating a group it's fine to treat appallingly. And...that's an environment where very bad things can happen.
Do I think that we are definitively headed towards fascism? No. Do I think we are creating a situation where it is more possible for fascism to arise? Yes.
Do I think Theresa May wants to murder EU citizens? Absolutely not! Do I think that if her government ultimately the normalises hardline xenophobia, someone with much more toxic ideas might take power?
I don't know. But I think it's more possible and that's scary.