IMO, it's probably a combination of factors. I get the feeling GitHub has no clear leadership by anybody who actually USES it. The priorities internally were almost certainly "get onto azure, shove copilot/AI down everybody's throat, and other generic "product driven" initiatives. The user-hostile move to react was done in a way that broke browser back-button functionality, especially in Pull Requests.

They don't/didn't care because what are you going to do?

On one hand, the free users shouldn't complain too much, though I get their anger. But the place I work is an enterprise paying customer and this is bullshit.