All GNU projects require assigning copyright to the FSF[0]. It feels a little absurd to call a GNU project "not open source".

But I would certainly trust the FSF not to change licensing terms (aside from moving to newer versions of the GPL/LGPL) to something unsavory, while the same can't be said of any old random project out there. I think that trust (or lack thereof) is the real issue. Ultimately, though, it's better to just not have to trust; I don't sign over my copyright to projects either, unless it's part of a job and the stuff that I write would otherwise be owned by my employer anyway.

[0] https://www.gnu.org/licenses/why-assign.en.html

The FSF requires copyright assignment so they can upgrade to newer GPL versions at will. I happen to disagree with that as well.

Agreed, and this is why I never have contributed to a project with a CLA.

Not even to e.g. something from the Apache Foundation? Or Eclipse? Or CNCF?

There are two organizations I would consider assigning copyright to for free work: the FSF and the ASF, which are both organizations with noble goals.

Certainly not the CNCF.

Yup! I might make an exception at some point but so far I haven't. I believe that all contributors should be equals and not some have more rights than others. Also I need to research and trust the entity which I sign the CLA with.