Because the `microsoft` group account is the owner of the repo. With group accounts, you can designate many individuals to have admin access to the repo, but the actions taken by those admins will be attributed to the group account that owns the repo. (Because presumably the rest of the admins agree with the action taken, otherwise they would undo/revert it).
I am reading all pings from GitHub on VS Code and this was just turning into a stream of spam that wasn't adding much new information.