In general, I don't think there's anything at all wrong with deciding that the goals a person or company is working towards are so objectionable to you that you don't want to contribute to their income streams and thereby support those goals.
However what the GitHub repo is an example of is straight up bullying. They're trying to force the Rails org to fall in line...
I mean why does the leader have to align with your faith. If this escaletes youll realize that people will discriminate patches of contribution because they came from some who is "muslim" or "christian".
It seems backwards to leave a blogging platform project because other people helping make that blogging platform have different views. They might even use it to make a blog about something you wouldn't. They might say something dangerous like the right sucks or the left sucks.
The internet was better without real names. The less people know about you the less prejudices you face.