It depends on the country. When I lived in Poland my father complained a lot about his union (Solidarność, he worked as an industrial electrician), as the management was mostly old people who did as little as possible to not lose their position, and did nothing outside of being in the union (they were retired). You would have a hard time outvoting them because you'd need to get a certain number of votes from multiple plants, around a thousand of people in total - campaigning alone would take most of your time, on top of doing your work. I haven't heard many positive stories about unions to be honest, and I lived in upper Silesia, the most industrialized region - where there were lots of them.
To me, the benefits seem obvious but I couldn't think of downsides. So I was, in fact, trying to broaden my views, just in the other direction, I suppose.
I've never felt the need to join a union but, fundamentally, I see nothing wrong with someone controlling their own capital (time, labor, and skills) and freely associating others to pool those resources into something that's more than the sum of their parts.
I can see where it might be a problem if a group ended up with a monopoly on some skill, but that's a problem with any kind of pooling of resources and we have tools to deal with such a distortion should it arise.
It's cool to have the worker protections laws here, but sometime it feels like unions are just useless/wastefull relics.
I would say in general, unions in Europe are viewed in a much more positive light. Collective bargaining allows for workers from blue collar to white collar work receive their fair share from the company.
I would try reading more about the labor movement in the US: https://en.wikipedia.org/wiki/Labor_history_of_the_United_St...
Please try and broaden your views. HN is an anti union echo chamber for the most part.