Well it was half in jest. Boxing is known to be dirty as **** and a few top MMA fighters have been caught out (Ubereem ) pretty much all sports have it at the elite level don't they? Even tennis was in the news recently. Cycling, running...you name it.
Since they brought in Jeff Nowitski to run the drug testing they have been tighter than tight on PED's. Highly highly doubt people will be using PED's for much longer. I recall Bisping got tested about three times in camp for the Anderson fight and Bisping has (as far as I know) always been clean. Imagine what serial dopers are tested like?
Jeff Nowitski by the way, is the man who caught Lance Armstrong.