That's the facebookisation or redditisation of open source. Open source used to mean when you got the software you got the source code, but now it means a platform for arguing. And there's no doubt in my mind when people say they can't switch their project from GitHub to Forgejo because they'd lose "contributions", they mean this.
I don't understand your point. The phrase "when you got the software it got the source code" makes no sense. And arguments were just as common decades ago on forums, mailing lists, and IRC. What exactly are you trying to say?
I would never look at a person's github account to evaluate them. The most important things people do will be proprietary, or if they contribute to serious projects will be in that project's gitlab/forgejo's instance.
I don’t think this is anything new. There’s been massive blow ups for as long as we’ve been doing this - NetBSD and OpenBSD was a massive, public falling out as was the gnome 3 release, or the python 3 release.