Maybe. That has not been the case for the big American companies I have worked for here in Sweden. We always got the same benefits, including stock options etc, as everyone else in the companies. Not sure what the unions would say if a company tried to punish workers for being unionized, but I suspect they would not be happy about it, and there may very well be something in the collective agreement they want signed that already covers this.
Ah, even the unionized Amazon workers in Europe get RSUs.
To cite Ellen Ripley: I don't know which species is worse, but I'm sure they wont let themselves get killed forba percentage". And not everyone, especially outside the US, is willing to do so neither.