I get that it's the gag of this manga, but dang if my empathy is not getting triggered by this talk behind her back. I've been in that situation before, where I overheard coworkers talk sexually about another colleague and it was icky.
I definitely get it. I like the manga because it's funny, and outside of the comments about her sexuality it's surprisingly wholesome how they get along (i.e., they're not outright being gross to her), but constantly objectifying her wigs me out*.
But I do wish they would just be friends and not care about whether she's an AV actress or not... But that might be the actual hook for its otaku audience they won't want to drop, which is unfortunate.
*(You see a lesser form of this in most Slice of Life high school romance manga -- the FMC always
has to be pretty, always a model, always the prettiest girl in the class / school. Even when they try to add details of them being socially awkward, otaku, or uh, say, bad at communicating... The #1 priority for the mangaka in every panel is always that they're pretty first, personality second. And that shit drives me crazy.)