Not really, not considering a fighter GOAT due to bad loses, poor fight choices or hanging about too long isn't looking down on that fighter.
I respect BJ Penn for example and recognize he did a lot in his career, but am also aware that the latter part of his MMA record losing 6 fights on the bounce cannot just be written off like 'ow well 11 years ago he beat Sherk...GOAT!!' these loses, these beating the fighters take don't mean we look down on them be they certinaly mean something in the whole picture of their career.
Choosing to think a fighter is the best ever in spite of his late career rather than choosing to believe he is not inspite of his glory days is essentially the same thing-Your not wrong, I'm not wrong, it's just a matter of how we see it.