I'd say
Ok. This could be your opinion, which no one can take from you...
But suggesting the most dominant WW champion to date, who took a couple of years off and came back to take a belt at a higher weight having never fought there is a "nobody" in any conversation is simply wrong.
GSP is in the conversation weather you choose to recognise him as one of the best or not. I'm not really a GSP fan. But stop being a twat. You don't like the way he fights... think he lost to Hendricks... yada yada yada... You're not alone in thinking this. But he's in the GOAT conversation like it or not.
To further twist your melon. Two of the other guys he shares this conversation with both tested positive for steroids (One tested positive for something like 5 substances), and a great many of the others fought in FAR less competitive divisions. But you probably knew that.