Yeh basically man this mindfuck of a website has made me analyse quite a bit over the past few years. I honestly think there is a separate category of men, who are exclusively heteroromantic and frankly usually exclusively heterosexual in their offline sexual experiences (though with a few exceptions), who have a shallow/hyperfocussed form of homoeroticism which I personally refer to as "penis fetish". There are quite a lot of men on the site like that, from what I've personally experienced over the last 11 years.
It's problematic on a few levels to call this "bisexual" though, because the implicit inference is the suggestion that the male form's objective aesthetic value can be boiled down to solely the genitalia. I think this is a large factor in the general male "penis obsession" (ranging from insecurities about size to extremely focussed, shallow homoerotic desire, to a higher frequency of gay/bisexual male size queens), and I think it is personally tied in with a concept called "benevolent sexism". I think some men that do engage in the whole "circle jerk" thing, probably exhibit this hyperfocussed, shallow form of homoeroticism, because from the anecdotes I have heard about it is usually visually focussed not mutually interactive.
My view is basically that it demeans the male form's full aesthetic value (and thus men generally), demeans LGBT people generally (by lumping in a hyperfocussed version of homoeroticism within this community, but not needing to go through any of the tougher life experiences that LGBTs have to go through) and it also justifies the objectification of women (but only certain types of women). So basically, it is actually harmful to almost everyone. I go into more detail on it in the women's issues sub:
https://www.lpsg.com/threads/benevolent-sexism.504411/