If Fedor can be considered the GOAT without speaking English or fighting in the UFC, then Aldo can as well.
There is no excuse for UFC's blatant favoritism, laziness, and lies.
TL;DR - I've seen the Fedor comparison a few times and there's a lot right with it, but there's also a lot wrong with it.
The ramble:
First off, Pride was as much spectacle as the UFC is now or even more. It was definitely NOT just about the highest calibre athletes fighting one another and anyone who thinks so has revisionist history problems. Pride was a fucking circus and any honest MMA fan that's been around long enough acknowledges that. So don't pretend the UFC is debasing a sport that's always been at least part carnival side show. The UFC was honestly a lot more honest representation of the best fighting the best up until fairly recently. Fedor himself has a resume full of lop-sided matchups and absolute cartoon fights, with the occasional fight of a monster ('sup Kevin) thrown in there to keep everyone's respect of the man's real skills.
Secondly, because of those self-same freak shows, can crushing matches and full knowledge that Pride tested for exactly fucking nothing, there are LOTS of people who question the legitimacy of Fedor's claim to GOAT. I'm not going to get into that, but I will point out the 'can be considered' in the quote above and say that it isn't the same as 'is considered'. Not in terms of unanimous anyway.
Now on the opposite side, Pride DID back the hell out of Fedor. They touted him as the best, they marketed that and they went along with the Russian Mafi...I mean M1 Global and kept that train rolling. That's about the only solid point the comparison has. The UFC couldn't, and never did, give a shake of piss about Aldo. The exposure, or lack of, totally showed that. To be fair, though, I never got the impression that Aldo gave a squirt about them either. He definitely was a man going to work to punch a clock in his later years. There's no love lost on either side that I can see. But he didn't necessarily hand the UFC a ton to work with.
McGregor just made it easy on them. When he was off injured, he somehow managed to spin himself as something to be watched when he got back. The UFC didn't BUILD him up. They just did what anyone wanting to seem like a leader does: see which way the crowd is running and then run to the front.