They usually blame 'girls in the club' a'la Gasquet, 'mothers' a'la Čilić, doctors, physios, coaches or even National Federations. But, that wasn't the case with Maria, she showed up there and said she has only herself to blame for this situation. I don't know whether you watched the presser or not, but she did say her family has history with diabetis and heart disease and that's why their family doctor gave her that drug.
She admitted this all is her fault, as she didn't check the list herself, but I bet that doctor has already gotten fired, lol.
And what makes you think she's a cheater? That drug had been legal more than a decade, of course in a test phase, but still. I'm quite sure every single top athlete takes some yet-to-be-illegal drug, just like Maria did. That could be anyone, Ana, Dafne, Novak, Andy, Jusain, Yelena, Serena or any other high-profiled athelete in the world. Human's body is not able to produce such results without any enhencement drugs - that's a fact. I'm not accussing anyone, just stating the obvious. Maria's case is not the lone one unfortunately.