This like if BitTorrent cut off Windows support over objections to Microsoft embrace/extend/extinguish. It’s a slightly incoherent position.

This seems like a tenuous analogy, to put it lightly.

Care to explain why, or nah?

To me it feels more like the old "this site only supports IE6". Instead of checking which JS engine the user has, check for specific api support and fail gracefully.

Not BitTorrent, but I can see a world where e.g. Transmission dropping Windows support because of Microsoft policies.

Which company doesn't do that?