As mentioned above, he's been caught using diuretics to illegally make weight. Ergo, he's a weight cheat.
So in general, the fact that he weighs in bigger than most of his opponents in ok with you? Then fine, we have no argument. My point is that plenty of people call him a "weight cheat" simple because he cuts a lot of weight and is bigger in the ring than his opponents. Something which LOTS of fighters do.
I think it's fair to not give JCC any slack for failing the test and I think it's fair to say some people are going easy on him because of who he is. Bringing up the diuretic positive testing is a legitimate argument too. There's certainly some sense in separating the effects of weed and a diuretic on performamce but the focus of the criticism does seem to be on his integrity which is a legitimate criticism.
I wouldn't say I'm 'Ok' with it, given that he's come in to ring sometimes 20+ pounds heavier than his opponent. There's a limit to what's fair and safe for the other fighter. However, it's legal in the rules as long as you cut and make up the weight again legally. For me there's still a question about that in regards to Chavez, as he has been caught using diuretics before, and more recently has refused to submit to post-fight testing on several occasions, which in itself casts suspicion. I just think the entire way he goes about his business stinks, to be perfectly honest. From his lazy 'preperation', to the diuretic use, his horrible 'style' and his goading of guys 20 pounds lighter than himself, saying 'you can't hurt me', as if it was something to be proud of.. To me he represents a lot of the negative aspects of the sport, and the more often he's beaten and kept off my TV screen, the better.
The other guys who rehydrate massively dont get the same treatment though. No one was callimng out Ortiz for weighing 164 against Floyd, and Margarito for weighing 165 against Pacquiao. Or Clottey weighing darn near 170 in his welterweight fights. For some reason though,people focus on JCC.] Also I think his "lazy" preparations are overrblown for the camera. They guy took an 11 round beating from one ofn the best p4p fighters in the world and then came on so strong in the last round,that he almost finished him. Also I doubt he outweighs his opponents by 20+ pounds. He'd have to weigh in the 190s forn that to happen and I REALLY dont think hes coming in that big. Most middleweights would rehydrate up to at least the high 160s, more likely well into the 170's You dont get get level of conditioning without training extremely hard.