I'd rather hiring a masculine gay man too but some posters prefer "gay-per-pay" escorts and a frequent poster only hires them because he's afraid a gay escort will tape the encounter and blackmailed him later...
Some truly straight guys might escort for gay men because they're very sexual or they just like to do it, others might do it as an act desperation because is their only choice of fast money. It's a fact that most of the times a client is hurt or blackmailed by an escort s very likely to be a straight guy who is secretly homophobic and ungrateful with the community that hires him.
Btw if you post a link to his ad I'm sure he'll get plenty of promotion here, many guys hire men others can't have for free and the fantasy of a straight guy is rooted among gay men.