I don’t understand how this comment actually responds to any of the issues the parent raises? I think they would have made a perfectly good comment if they hadn’t spelled out the issues with the non-GitHub system but they seem to have taken the time to address many of the things you write about in advance (unless they edited that part in after your comment).

Fwiw I also think you’re missing the point about the increased barrier to entry. I suppose one could make arguments from first principles about which platform has the higher barrier to entry but actual people don’t start from first principles – they are much more likely to be familiar with GitHub (I have weaker priors for eglot contributors but I still expect potential new contributors to be more familiar with GitHub).