@bjoern Non-free JavaScript can be replaced---it's served on the client, so you can exercise the freedom to modify it. The userscripts community has experience doing this. But as you note, it's not very practical; my LP2016 talk was all about this problem and some suggestions on how to solve it. (https://media.libreplanet.org/u/libreplanet/collection/restore-online-freedom/)

So while a full stack is indeed necessary, I agree, non-free JS is a complete non-starter to the point where I can't even _collaborate_ with people using those communities. If a project is using SaaSS for their work, they are sacrificing their freedom (not the four freedoms---different kinds), not me. If I choose to contribute to project Foo, it doesn't matter to me if they're using gitlab.com or hosting their own GitLab instance---I can't modify it no matter what. But that's okay for me, because it's the _project's_ tool, not my own.

I can collaborate with a project on GitLab no matter where it's hosted (https://about.gitlab.com/2015/05/20/gitlab-gitorious-free-software/). I can't collaborate at all on GitHub, though, because I'd have to run non-free JS. I recently submitted a patch for a Minetest mod on GitHub and I had to paste the diff into the body of an issue---I couldn't create a pull request or upload a file! (But I think there's a CLI I can use with their API; haven't tried it yet.)

Of course, proper federation would solve this problem entirely, if I could collaborate using my own instance. :)