Jumping in a little late but I read through the thread.
My main thought here is that “Casual Sex” is vague, “into casual sex” is vague, and the particular motivation of the OP is vague for finding somebody like this is vague (from my reading, doesn’t appear to be, for example, a religious motivation). In fact, it seems more like the OP is assuming that those guys who aren’t in to casual sex will make for better relationships.
IMO, Both camps are going to far with their characterization and stereotypes of people in the other camp (casual sex vs. no casual sex). I, for example, am a pretty nice guy, currently looking for a serious long-term relationship. However, were I to meet a girl I’m interested in and have a good time with, I would see no problem whatsoever with having sex with her. Am I into casual sex then? I would be interested in calling her and pursuing her further in all likelihood, so does that make it less casual? Does it rule me out by the OPs standards? More pertinently, does this seem to make sense? I’m curious as to what, exactly, it is about the fact that I’m willing to be physically intimate quickly makes me worse as a person, and (presumably) worse as a relationship partner. (Also note that I’m willing to NOT be immediately physically intimate, should my partner so choose, but would quickly become worried about the POTENTIAL for physical intimacy if my interest <but not yet relationship> continues to “hold out on me” for no immediately apparent reason)
On the other side, it seems like the people “supporting” casual sex are assuming the worst about the people who don’t. Unfortunately, because the definitions are so vague, it’s easy to insult them as religious/anti-social/crazy people.
I would say I only have a problem with people who seem to create arbitrary rules about sexual involvement. Everybody knows or has a friend who seems to have some sort of calender with dates marked off when s/he can “start” doing something with somebody else. Said person often agonizes over particular people, and how much they want to do X, Y, or Z (or XXX…) with that person, but can’t because “it’s not time yet”. Setting artificial dates, or holding off in order to “test” somebody accomplishes nothing, and really, drives away a lot of potential suitors who are suddenly concerned as to the level of involvement between them. I take it as a warning sign of sexual and personal instability if people are intensely concerned over whether or not something is “official” or “too soon” or “too much” when their body and mind are telling them it’s what they want. Self-Denial in this way accomplishes nothing.