It's cos they're black, the answer you want to hear OP, and the answer that's increasingly becoming hard to deny. There's other factors at work as well, but those same factors are conveniently written off for popular white fighters.
America loves to think it's race baggage is all in the past, but there is a lot of subconscious or low key racism still around.
Yeah bones is so arrogant, yet Sonnen is "a lovable rogue" for 10x the arrogance + cheating, and Henderson is a "legend" even though he's a 40 yr old using a TRT loophole and hid his injury but shares no blame for 151.
Yeah bones committed drunk driving, extremely stupid but fortunately he hurt no one. But some freak called "Mask" Lewis in face paint gets completely sloshed, recklessly DRUNK STREET RACES his porche with a female passenger next to him, kills himself and leaves the girl in the ER and what happens? Nationwide mourning and induction into the UFC HOF! For a guy that wore face paint and sold T-Shirts leaching off MMA's popularity without having fought a day. Yeah his death was tragic but what he did was MUCH WORSE than what jones did, yet he is a great example and some sort of martyr?
Don King was a crook and uneducated bum, but Dana is a shrewd and amazing businessman, who "speaks his mind", and in shafting the fighters pay wise he's just building mma.
Bendo sucks because he "didn't really win" that second split decision clearly, even though that's the judges call not his, but Forrest was the "people's champ" for his crappy pillow punching decision over Rampage, and no one holds any of the dozens of other split decisions against the winners.
Anderson is the GOAT, but his PPV buyrate is the lowest of all champs until the great white hope comes around to challenge him with steroids.
Rashad is virulently hated for hardly any reason, until they finally found a blacker guy to hate more than him and cheer him against.
Rampage is loved but only as long as he plays the chain wearing thug stereotype that likes to commit black-on-black crime.
And yes, the Johnson fight is awesome until the decision is announced and now everyone hated it.
I used to not want to believe this kind of stuff, but too many coincidences, it is what it is.