Um. How does having 700 books in your room make you an expert? How do you even fit 700 books in your room? I have a shit ton of philosophy material but merely having it doesn't make me an expert.

The question was what other philosophy the person had been exposed to, and it was answered rather satisfactorily in this context.

To choose Rand after reading the few but vigorous engagements/rebuttals of her entire thought

that's never happened, and I can't imagine where you'd be getting your "facts". Compare the Nozick and Huemer critiques against the likes of Rasmussen-Den Uyl and Peikoff, and it's not at all difficult to understand how someone would think that Rand's ideas stand up just fine. (Given Understanding Objectivism, it's difficult to imagine how Rand's ideas couldn't possibly stand up just fine given its entire commitment to, uh, you know, epistemic perfectionism or something like it.)

and reading up on multiple different philosophers, or at least books called 'intro to logic' and 'intro to ethics' seems rather more satisfactory than bragging about how many books you have. Actually engaging with more than a fraction of 700 books seems like more than a mere BA worth of work.

This latter statement is true; it would probably amount to PhD level work. Having a ton of books doesn't prove anything by itself re philosophical understanding. But having that number of books is a good prima facie sign that the poster has been exposed to quite a bit of philoophy aside from Rand.

The idea that it would be incomprehensible for someone to study widely in philosophy and still be big on Rand, is one of the rather nasty prejudices of many in this "philosophy" sub. There are quite a number of professors and PhDs in philosophy who are big on Rand and they almost surely understand Rand/Peikoff way way better than the often-nasty critics.