Being downvoted for an unsubstantiated blanket claim like that doesn't even begin to suggest a bias. The only way such a comment wouldn't be downvoted would be

Being downvoted for an unsubstantiated blanket claim like that doesn't even begin to suggest a bias. The only way such a comment wouldn't be downvoted would be if there were a widespread bias against the person in question. Pick a random person. If you posted this exact statement about them, would you expect to be downvoted? Personally, I'd downvote it regardless of who it was.