"I should have reflected on what it meant to not be on the same side of a movement largely led by young producers of color"
That's basically it in a nutshell: the quality of a movement, of an argument, of an opinion is to be judged solely by the minority or oppressed attributes we can find in its supporters.
It doesn't matter if PJ was against the unionizing for his own reasons whatever they might have been -- how they might have affected his benefits, financial reasons etc. His stance against the unionizing is viewed as a personal attack on the attributes of the supporters -- young people of colour.
Put another way -- is there any objection that PJ could have raised to the unionizing efforts that would not have resulted in this same outcome? I doubt it.