It is a private company, alright, but it is also becoming a critical company for the internet as a whole
Hardly. OSS was in a very healthy state before Github and it will manage just fine without it. I'm not saying Github doesn't add value - it absolutely does - but if it died tomorrow, I'd simply create an account at a different vendor, push my repos to it, and pick up the pieces from there.
Distributed VCS are uniquely great in allowing one to switch hosters without much of a hiccup, yes.
I was referring, though, to all the surrounding aspects of GitHub, e.g. issue tracking / discussions and discoverability. Quite a lot of projects have no online presence except GitHub pages. Let me again draw an analogy with Facebook: Of course there are many ways to contact people - (e)mail, phone, instant messenger - but a lot of people rely on Facebook to stay in contact with each other and don't bother to exchange other contact information.
Besides, censorship is far more subtle and pervasive than closing shop. It changes the perception and values of the community, instead of driving the participants to some other place. Also there are surveillance and subversion issues. When it becomes common to install binaries directly supplied by GitHub, I better trust them not to include any (targeted) malware.
I get it, I just don't think it would be very hard to migrate those things. You'd probably even be able to download an OSS tools from whatever GitHub replacement you'd be about to migrate to.
I'm not sure I'm with you on the second point. I think I understand where you're coming from, but I think it's a reach to their from this incident. Being required to use civil language on a public site seems like a reasonable requirement to me.
