Some people are absurdly optimistic. Craigslist is an excellent example of this. Men write post after post, knowing that they're unlikely to get anything better than a link to a paysite.

Nowhere is this optimism more apparent than in the m4ww section. 

It's a sad reality that men are much more open to casual sex than women. Women are socialized to think casual sex is slutty, and we also have good reason to worry about our safety, so CL -- where people try to hook up with strangers for random fucking -- has a lot of frustrated straight guys. And really, beggars can't be choosers. Some people haven't grasped this yet.

I WANT WOMEN TO RUN A TRAIN ON ME:

i always wanted a few girls to make me their jump off and take turns making me fuck and suck on their cunts till they nut cute CLEAN shaved or waxed no hair down their girls 
me and a few friends gang banged one or 2 women back in the day don't ask because i wont tell i always wanted to know how the women felt 
or how i would feel if the tables were turned lol im brown skin 5'5 really cute i know how to lay pipe and eat a mean cooch something every man should learn 
to master must be at least 2 women so bring a friend OR 2 AND SHAVE YA PUSSY 

This is the kind of guy who encourages my evil side. 

Hi! Me and my friends have been looking for a guy to play with for a while, but we haven't found anyone uncreepy. I'm 5"4, 110, 32D redhead. My friends are both slender blondes, and we're all pretty hot. We all have nice thick bush, and we're not interested in shaving (razor burn, stubble) but if that bothers you enough to turn us down, we can always find someone else. Interested?

Here's the thing about guys who post on Casual Encounters with a list of requirements -- "You must be thin, white or Asian, multi-orgasmic, at least a C-cup, totally shaved, willing to take it bareback" -- you always wonder whether they'd actually turn down a hot black woman with a little extra weight. If they're posting on CL, they're pretty desperate.

Of course, my hypothetical sexy plus-sized black woman is a woman, on CL, in casual encounters and she can do whatever (whoever) the fuck she likes. If she posts an ad she'll be inundated with penis pics within ten minutes, and the guy she'll choose will probably be much hotter than the loser looking for slender white women only.