" Why are collective agreements intrinsically bad?"
Because I should be able to do what I want, instead of being forced to go along with whatever stupid ideas the union chooses to do. It is called freedom of choice.
What if I want to negotiate for myself?
What if I want to wear multiple hats?
What if I want to work without getting a BS certification?
If I negotiate, and convince someone to hire me, then I can get all of these things.
We can agree and disagree about what makes a work environment good or bad. And thats fine. Just you do your thing, and I will do mine. If you don't like these things, then you can try to get a job that doesn't make you do them.
My relationship should be between me and my employer. I will negotiate all the things that I mentioned, and if the situation doesn't work out then I will vote with my feet and go somewhere else. Do not take away my right to free association.
Sure, fine, if you don't like doing those things, then you are free to join your own private organization and decide for yourself on how to do collective bargaining, and all that.
The problem with pro-union people is that they assume that their needs are the same as everyone else's needs. Different people want different things, and this whole "fight for the people" BS gets thrown out the window the moment you try and force me to join your org and force me to go along with stuff I don't agree with.
"And, of course, if you really don't want to work for a unionized workplace you can go and work at a non-unionized workplace."
Well, instead of doing this thing, I could just use the law to protect me. Forcing people to join unions is, thankfully, illegal in many states.
And, thankfully, unions are very unpopular among techies. So I am doing precisely that, and I will continue to fight against them in tech, precisely because I do not want our industry to be turned into one that does not value freedom of choice among employees, and forces different people into associations that they don't agree with.