Granted, her name has a better brand than Yahoo still, but she's working on that. What you said sounded sexist, and I'm not even a feminist or a female.
Perhaps he's pinning the blame on Mayer because the announcement was written and signed by her! It's the role of the CEO to represent his or her company in this manner and serve as the lightning rod for any feedback. The fact that Mayer is a woman is completely irrelevant. Both Jobs and Gates (and many other male and female CEO's) took on that role, and there is absolutely no shortage of rants and raves over the years directly addressed at them.
In fact, I would say that you are the one being sexist, since you are apparently accusing jpdoctor of sexism based solely on the gender of Yahoo's CEO.
It's not unexpected for newly-joining execs to be blamed for recent decisions.
"What you said sounded sexist, and I'm not even a feminist or a female."
Possibly because you don't understand what a feminist perspective is? There are plenty of ways to be sexist, but strong personalities, male and female certainly get associated with brands.