Perhaps has to do with the Github sync feature, https://cursor.com/docs/origin/mirror-github
It's one thing to have low quality products, it's another to have a low ethics leader. They can both be hated, but it is different.
GitHub downtime is a matter which can be resolved, not so sure about Elon's antics. But this is all besides the actual reasons GitHub has staying power. (network, actions, migrating git hosts is a significant endeavor that doesn't add value to your users)