> I refuse to contribute to any project that requires me to give them copyright instead of contributing under copyleft
Please note that even GNU themselves require you to do this, see e.g. GNU Emacs which requires copyright assignment to the FSF when you submit patches. So there are legitimate reasons to do this other than being able to close the source later.
FSF and GNU are stewards of copyleft, and FSF is structured under 501(c)(3). Assigning copyright to FSF whose significant purpose is to defend and encourage copyleft…is contributing under copyleft in my mind. They would face massive backlash (and GNU would likely face lawsuits from FSF) were they to attempt such a thing. Could they? Possibly. Would they? Exceptionally unlikely.
So yes, I trust a non-profit, and a collective with nearly 50 years of history supporting copyleft, implicitly more than I will ever trust a company or project offering a software while requiring THEY be assigned the copyright rather than a license. Even your statement holds a difference; they require assignment to FSF, not the project or its maintainers.
That’s just listening to history, not really a gotcha to me.
I will start being worried about GNU approach the day they accept VC money.