It was the premature perception of Weidman, and the overrated career of Vitor.
I'm not for one second saying that TRT completely nullifies your career or your wins, because I don't hold everyone to the same standard. My issue comes in when you clearly look one way, and then you start openly having TRT and then almost overnight become the most dangerous fighter in the world.
Look at Dan Henderson for example, with or without TRT, always an elite fighter who was fighting and beating some of the best in the world. You look at him post and pre TRT and he looked in good shape as well as being a great performer in the cage.
Vitor Belfort on the other hand, came in at 19 looking like the hulk (which was pretty suspect) - blasted through bums, and even had the UFC calling him a former Heavyweight champion for years. They recently (last 5 years or so) have stopped that sort of promotion, but I can cross my heart and hope to die that Vitor used to be described as a former Light Heavyweight and Heavyweight champion. Pretty sure it was in the build-up to the Silva fight, where they were acting like he could be the first to be World Champion in 3 divisions. That man was never a Heavyweight champion, period.
He then goes on a muddled run through UFC and PRIDE where his best wins were Herring, Yvel and a pretty bogus win over Randy, which Randy avenged within 6 months and brutally stopped Belfort in the rematch. His next win of relevance was Matt Lindland, a considerably smaller Middleweight, good win, but still not setting the resume alight.
Upon his return to the UFC he had wins over an aging Franklin, still a great win and Sexyama (oh please). Since then he was wasted by Jones and Silva, and then he all of a sudden becomes a cyborg overnight and is throwing head kicks from hell and wheel kicks from heaven - I'm calling bullshit on that run, it was so manufactured by PEDs it's unbelievable.
Oh, and then he comes off PEDs, and all of a sudden his black belt in BJJ becomes a belt you find in your happy meal. Mounted and demolished in 3 fights, in quick succession.
Losses to all the big-boys, other than his PED driven streak - FACTS.
Mousasi
Souza
Weidman
Jones
Silva
Henderson
Overeem x2
Ortiz
Couture x2
Liddell
Sakuraba
Chris Weidman, why is he overrated? Well here we go:
Weidman is a top fighter, there is no denying that, but his resume is ridiculously small.
He is spoken about like he's a dead-cert, elite level fighter who was the future of the division and of the sport. Everything from his cheesy push as an American hero type, to his bogus wins over Anderson just put him on this ridiculously high pedestal, way before it was deserved and earned.
It's not his fault that Silva goofed around and presented his chin on a platter, not Chris' fault for taking the opportunity and KO'ing him. Unfortunately for Chris though, it's just tainted. He didn't go out there and dominate Anderson and win with a clear-cut victory, he caught the master of taunting with a punch and put him out. If you watch the fight closely you can see the tide is turning and Chris' first round momentum is dying, he's getting slower and is eating heavy kicks from Anderson - that fight is only going one way and that is a late Anderson stoppage or 49-46. Weidman in a way, got lucky.
Now you flip it on it's head and Chris in my opinion was well on the way to victory in the second fight. He was all over Anderson, and might have actually finished him in that fight, but once again (not his fault) but a freak accident happens and it's all over. He then has 2 wins over the arguable GOAT and neither of them really felt totally legit.
His win over Machida was legit, and I'm not willing to accept the narrative of Weidman haters, who claim Lyoto was "old". He was on fire leading up to that fight, so I will not accept that. That by far was Chris' best win, he out-struck Machida for 25 minutes and also fought through adversity in the 4th round, great win. The Vitor win wasn't great for the resume, because not only did he actually get blasted and almost finished against the cage, he fought a deflated and old Vitor who was off PEDs - that wasn't the same Vitor we grew to fear.
Immediately after that run, he has 2 fairly competitive fights with Luke and Yoel - but ends up a mess by the end of both bouts - 2 of the most brutal finishes I've witnessed in the sport.
So yeah - hope that wasn't too long winded