As someone from a "white working class" family in the trades, I can tell you, anecdotally at least, that the emptying of militancy from labor unions has been decisive in opening up white workers to the right.
Sorry, this attempt to blame "PC culture" for white reaction (e.g. not "knowing one's real interest") is total bullshit.
And I say this as someone who finds much of today's discourse distasteful and frustrating. I think trauma-talk has become a tick in left subcultures. But this is a cultural frustration that is totally divorced from the "white working class" situation, if you want to call it that.
If the only way you can relate to the "white working class" is through racist jokes, maybe it's because you only share the "white" in common with them and less so the "working class" part