That's not self-hosting. That's getting services from a third-party organization that happens to be a non-profit. The only difference between that and GitHub is that GitHub is a for-profit company, which setup and maintain services for you (for free or a small fee).

So if the actual complaint is "stop supporting for-profit companies," sure (but then we have to ask why - there are reasons to expect that a for-profit company is likely to be more stable long-term, more likely to be secure, etc.). If the complaint is "GitHub / Microsoft in particular is bad, and chatons in particular is good," sure (but then, what about for-profit competitors like GitLab?).

But that's unrelated to the original complaint. As you say, chatons is maintaining OSS services for you to interact with.