Nazo on Nostr: One thing I've always wondered is why group access isn't ok if the group is the ...

One thing I've always wondered is why group access isn't ok if the group is the user's own named group (eg if username is Person, the group name would be Person.) Which is going to almost always be the case with anything in the ~/.ssh directory anyway. I get the security implications of allowing anything else access, but why is the user's own named group not ok?