It's more about priorities and intentions. Microsoft doesn't care about the developers. It cares about having the dominant platform. It recognizes that its image makes that difficult.
The GitHub acquisition: Microsoft didn't suddenly get more beautiful. It put on a mask. It will kill GitHub - or at least let it flounder - if that's what's best for its business. It will push Microsoft technology into the GitHub user base if necessary.
Developer relationships aren't an end in themselves - something Microsoft wants because its good. Developers are a means to an end, and its Machiavellian in its application of corporate strategy to achieve this end.
Microsoft would happily buy Ubuntu Canonical if they thought it would win them either a market advantage or a way to push Microsoft stack into the Linux userbase.
Some people probably don't have a problem with that. I do. But maybe I've got a chip on my shoulder from seeing this go badly so many times.