You should listen to what people here are telling you about your misinterpretation of the situation (even the ones who seem to you to be being jerks about it). You might learn something.
Here's a similar mind-bender: someone can like you and want to try moving ahead into some intimate contact, and your reaction to that can turn them right off. Being really uptight about the thing, showing that you're ready to be "hurt" if things don't go as you want, demanding explanations--all these sorts of actions on your part can change someone's mind about you. If you're not aware of how those actions can do that, it can seem to you that you've been led down the garden path and then rejected "inconsistently" or "cruelly."
I don't presume that the woman you mention was not stringing you along, but even if she was, you are responsible for letting yourself be "hurt" by her. It's funny how little in human interactions can properly described as one person doing something to another; it takes two to do the dysfunctional tango.
I wish you better luck next time you like someone. Better than luck, though, is knowledge and honesty with oneself. Hard stuff, but it makes life better all around.
(P.S. Looking for explanations for your situation in speculation about genetic dispositions toward cruelty is not a step in the right direction.)