It's not a vendetta but publishing a story about how a specific person is a sexist who can be easily identified isn't exactly a very fair thing to do to that person when there is clearly a non-trivial likelihood this was not actual sexism.
It's hard to not be ageist, but in this case I think there was some of that "she's half my age so why is she higher ranking than me" involved.
But you're definitely right that there's not much evidence here. I can still make assumptions no matter how much of an ass they make me.