I don't think most people are saying that Brock SUCKS.
I think they're saying that he's just an unproven 1-0 MMA fighter who doesn't DESERVE to headline one of the two biggest UFC events of the year based on his sport-based credentials - but is only able to do so based on his fake pro wrestling background and the accompanying star power he built up in the WWE.
That's what people find objectionable.
The undeniable fact is that he's certainly not getting all of this hype and marquee status because of his actual legitimate wrestling credentials.
After all, there have been other amateur wrestling champs who have come into MMA without even a minute fraction of the fanfare and buzz that Brock is getting.
Oh, and all of those guys that you listed along with Brock - except for Sak - were actually NHB fighters first - who then did pro wrestling either on the side or at a time when a full-time career in NHB was not financially viable.
Otherwise, no pro wrestler - or anyone really - who has never faced and beaten one credible opponent (like Brock hasn't) can be considered to be a credible MMA fighter already.
Not even Sak was - that is, until he beat Conan to win UFC Japan (and then kept building on that first big win with a string of some of the best wins in MMA history).
Otherwise, he would have been left as no better than a Takada or Yoji Anjoh - just a fake pro wrestler who failed at becoming a legitimate MMA fighter.
Now if Brock goes on to have a Sakuraba-like career in MMA, THEN he'll be remembered more for being an all-time great MMA fighter than just a former pro wrestler.
But as of now, that's all he is.
Do his sport-based credentials alone actually merit his already huge marquee status?
Of course not.
But he's there because of his WWE-built fame and drawing power - NOT because he's a former NCAA wrestling champ.
You can't deny that.