For someone with no interest in marriage, you sure put a lot of time into defending and securing long term relationships. I'm more interested in meeting a girl I like and having fun together than trying to analyze her like an investment and looking at what may or may not happen years down the road.
This is the same argument you put forth in the boundary discussion: that men are not putting up boundaries because they are scared of losing a girl. To which me and others responded there is no need for these discussions because a girl will show you she acts in the right way on her own, or else you would get rid of her, thus making the boundary talk pointless.
Obviously you do not "filter out sluts with impunity" because you dont know how many men your girl has slept with. Personally it isnt something I think much about, you can get a fairly good idea of a womans past and tendencies just by getting to know her. You act as if theres some slut registry where we can gather all the names of the "sluts" and delete them from our potential dating prospects.
If I like a girl, I continue seeing her. If I dont, I dont. If she looks like a used up white trash stripper then obviously I will not be attracted to her. But as I said earlier at my and your age Id be much more concerned if the girl hadnt slept with anyone or just 1 or 2 people than if she had slept with ten.