> It always seems to degenerate into an "us vs them" sort of thing

It is "us vs them". They just apparently understand that a lot better than you.

> Don't care about the union's bullshit "industrial action" and just want to work and earn some money? Get used to being called a "scab".

If all that's happening is you get called a scab then count yourself lucky. That's a sign that things aren't that bad yet.