Exactly. Because that, along with the article itself, suggests that the unusual compulsion is not a strong opposition to sexism.
Ad hominem concerns apply to rational arguments. This piece is not cool, rational discourse. It's a highly emotional piece, written to incite emotion. Inquiring about the source and nature of the emotion that drives it is fair.
He probably didn't notice sexism until it became personal. Why is that wrong? Most people become activists when something personally gets in their face, rather than through some abstract idea of "justice".
It's not wrong as such. It's just shallow. Hopefully it's the beginning for him of understanding sexism more deeply.
I do think it's wrong for a writer, though. If you're going to set yourself up as writing an article about a topic, I think you should actually know something about the topic.
This would have been a better piece if he'd made it more explicitly about his own feelings all the way through, rather than trying to make it about bigger things.
Ad hominem concerns apply to rational arguments. This piece is not cool, rational discourse. It's a highly emotional piece, written to incite emotion. Inquiring about the source and nature of the emotion that drives it is fair.