Would it blow your mind if I told you that both Anon and Ratgirl are in fact equally regarded in this situation?

There's nothing wrong with a person having an interest, especially an interest they're passionate about, but it becomes a problem when that one interest dominates their entire life, and is the only thing they're capable of talking about. At that point it's not even an 'annoyance' issue, it's a 'this is not good for your brain' issue. Dismissing Anon's attempt to change the topic and changing it back to her rats is a bad move.

However.

Anon was no better in trying to dismiss her conversation in favour of one he alone was interested in too. I'm not sexist, but I'm just gonna throw out some numbers here and say that at least 90% of men love cars, and at least 90% of women have zero interest in cars. Statistically speaking, if Anon tried changing the topic to sports, beer, or lesbian pornstars, he'd have gotten the same reaction from her. It would've been far more sensible to change it to something more neutral, like 'seen any good movies lately?'

Basically this was a match made in socially awkward heaven and frankly these two assholes deserve each other.