There is plenty of caselaw I can find where, for example, employees have not left, but refused to sign over patents on stuff done in spare time, and companies sued to recover them while the employee was still working there. I have yet to find one where the company lost.

For open source work, if you go through the process, it's short and we're happy to approve it (patches take about 30 minutes, projects, 3-7 days). In the IP release process, it's longer. That is better than every company i have worked at.

You seem to think it's not very important, and just nonsense in general.
Knowing who the legal copyright owners of the source code in your open source project are is quite important (in the cases you posit where everyone is just saying "whatever", the owner is unclear) If you don't think so, I can tell you in the one important case in the US where an open source project had to defend itself, Jacobsen v. Katzer, that Victoria Hall (the lawyer) spent a very large amount of her time trying to get all this sorted after the fact, and it is only by luck that the 50+ contributors she had to wrangle were still around and accessible.

This is probably 300k in legal fees that could have been saved by having done the right thing up front at a cost of about 30 minutes. Note that these legal fees were paid by the poor guy who was running the open source project, not by his contributors.

If you want me to be blunt, no offense, I've met folks like you, who think all this is a waste of time, and you are generally not worth the eventual expense in legal fees to the open source projects you contribute to (IE when the open source project needs to actually defend its rights, or the company behind the OSS project gets sued). Shrugging and saying "whatever" also has a funny way of turning into "that was really mine and guess what, we want damages" when the company you worked for gets bought.

It's great to want the world to be different. I support all efforts to make life better for engineers around owning stuff in their spare time. I also spend a lot of my life trying to help open source in general.

But to be blunt some more: The world we live in right now is not a happy pretty place. The reality is if folks like me, and the companies we work for, tell you than when you release a new open source project we probably own, that you should spend 5 minutes filling out a 4 field form and waiting a day for some folks to click approve before you fly and be free, it's not because we are power tripping bureaucrats. It's because we're trying to save millions in legal fees when it matters, and make sure the open source project you want to release is not going to be in a bad place, at a cost of 5 minutes of time and a small amount of waiting.

So my advice is if you think you really want to "call someone's bluff", I would instead think hard about whether you are really expert enough in this stuff to be able to say it's all nonsense, and stop to think about whether the people who are perpetuating "nonsense" may actually have your best interests at heart. That is, trying to save you from yourself. If you really think it's a great idea to have an awesome open source project used by 1 million people, when it's not clear who actually owns the code, then all i can say is that i pity those people.