I can think of at least four groups of people who would be interested in those ads.
Bisexual men - pretty obvious, really.
Bi-curious men - sex lines are a pretty safe and anonymous way to experiment with your sexuality.
Closeted men - similar to #2. If you want a gay sex line phone number, and aren’t willing to buy Throbbing Tube Steak Monthly in person, buying a Hustler is a good alternative that maintains your cover.
Gay men - even if a guy is willing to buy Throbbing Tube Steak Monthly in public, he might not live in an area where it’s available, and have to rely on Hustler for their gay phone sex needs.
I’m guessing ad space in a porn mag is not especially expensive, so none of these possible demographics needs to be particularly large for the advertiser to get a positive return on his investment.
I feel your pain – I’m a mod on another board, rolling this bounder uphill while repeatedly and futilely attempting to get the admins to add some Anti-Spam 101 features like “reject new user’s first posts if they contain a link or non-English character”. :smack: