You’re comparing apples to oranges with such a small sample size. I could easily counter that Bernie Sanders hasn’t been involved in as many scandals and that’s why the media didn’t focus on them — because there weren’t any. Scandals are good for ratings so if there was any such dirt on Sanders the media would have been all over it (I want to make clear here that I’m not even a Sanders supporter so you don’t interpret this as me just standing up for my candidate).
But regardless, you’d have to show deferential treatment to many male politicians versus many female politicians to say that it’s just about sexism. Since she’s the only woman in the race, negative attention on her could be due to any number of other factor, including her unscrupulous behavior.