That is a radically different use of Unionization compared to the typical "Fair pay and safe working conditions" demands. I'm struggling to see why unionization is an appropriate way to secure this kind of power, and why workers deserve to have any more say besides voting with their feet individually.
Unlike compensation, which is on a continuous scale and has multiple axis (comp, profit share, benefits, PTO), these kinds of decisions are fairly binary and therefor have very little room for negotiation.
Is this something where workers deserve the power to collectively bargain? To me, whether or not to support "Always Punch Nazis" is a truly nuanced and difficult choice and I'm not sure going one way or the other qualifies for "exploitation" of the workforce.