It's a lot like insurance - you might be fine right now, and you may be fine for your whole life, but what if you aren't? There are so many scenarios where you can fall out of favor and where collective bargaining is the only lever you have to pull against a large company. The chances are relatively small for an individual, but with the # of people involved, it happens a lot (we see HN post about workplace retaliation and employment litigation all the time).

And then, of course, there's the argument that those that truly need the unions could be your kids, your relatives, people you care about.

I don't think you need to be so concerned about subsidizing others; we all already benefit from that. This stance of being so protective of your labor should be reserved for employers and the Capital class, not weaponized against fellow workers to throw them under the bus.