Your argument doesn't hold any weight, imo. We're looking at entire careers, and currently Fedor has by far had the best career. He could lose his next 2 fights and probably still be the best all time. Hughes isn't even close, even before he began his downfall, losing against BJ, Alves, GSP twice, and possibly Charuto, he had already lost to Hallman twice and Pele. Gracie and Frye, come on man, thats laughable.
The only person worth mentioning in the GOAT discussion is Anderson Silva, and although he's been on a roll he has 4 losses, including Takase and Chonan. The greatest current p4p is debatable, between Anderson and Fedor, but the GOAT is clearly Fedor.