This is what people forget about GitHub. Its popularity isn't because it has the best tools on the market. It is popular because of the network effect. It's the social network of developer tooling.
I don't really want to be using a Microsoft product but I use github for the same reason I use Linkedin: because it benefits my career to be visible on these social networks.
That kind of ideology is great in principle, but if you struggle to get a job because you have limited presence in an employer's market, then you're practising deontology without a profession.
I'm an opinionated MS-hater, like most of my peers who lived through 90s Microsoft, like I had. But I also have a family to feed and bills to pay. Sometimes pragmatism trumps ideology.
I don't really want to be using a Microsoft product but I use github for the same reason I use Linkedin: because it benefits my career to be visible on these social networks.