yeah, i read their response as well, and it doesn't make any sense. USADA is a testing agency. their job is to test, according to the rules agreed to by both parties, and report their test results to the commission. they don't get to decide whether or not someone is exempt, that immediately puts them in a conflicting position. it's like saying NSAC doesn't do out of competition testing, so any positive out of competition test can be disregarded by USADA if they deem it exempt from the rules. it's retarded, and goes against the most basic principles of anti-doping testing.
i have no evidence that USADA is wholly corrupt, but there is glaring evidence that some of their practices are shady as fuck. considering their lack of transparency regarding tests, i have absolutely no reason to trust them.
besides, their story regarding mayweather was that he was severely dehydrated and needed the IV. he weighed in at 146. the most he'd ever weighed in at was 150 vs alvarez, and the fight was signed at 152. to believe he was severely dehydrated for a welterweight fight is extremely naive.