> the enthusiasm for tearing Mayer down comes from the fact that she was lauded as some kind of exceptional executive
While some of the comments are no doubt rooted in the perspective you mention, there are also plenty of overtly misogynistic comments about her too. I think it's a bit of whitewashing to claim that all the enthusiasm for tearing her down is strictly disconnected from gender. I don't know how you can read the comments that go by on reddit et all and pretend that elephant in the room isn't there.
I think a lot of the criticism of Balmer is specific and factual, but that people also overlook that on raw financials his tenure at MS was successful.