See current situation where the Carpenters' Union in California is pushing hard against an initiative that would make it much easier to build more housing in the state because it would also reduce requirements for union labor.

Unions are very much an in-group vs out-group phenomenon (and in many cases, the benefits are specifically to the more senior union members vis a vis the less senior ones.)

I can't speak for the OP, but I don't think their point was that they're against the self-interested nature of unionizing.

I read it more like they're against trying to stop, hinder, or prevent the use of new technology, simply because it's personally threatening.

And I feel the same way. If I was part of a union, I would believe in the collective bargaining power, but I wouldn't necessarily believe we should use that to pursue every single possible agenda that might benefit us. And I've personally pooled my capital with others in the past in order to achieve certain outcomes. And in those situations I also didn't attempt to reach so far as to limit the totally valid freedoms of others just because I knew it might be better for me.

Acting in the interest of a collective doesn't mean one must also abandon the ethics they usually employ when acting in their solo self interest.

their point is while the 'group' wins, the rest of the world loses.

localized gains, distributed loss.

Have you ever not been able to send your kids to school for weeks (or years in the case of COVID) because the teachers refused to work? Have you ever been unable to get timely medical treatment because nurses refused to work? Have you ever been unable to work yourself because the transit workers refused to work?