You want rationality, look at pickup artists. They have (questionable at best) goals, and they do whatever it takes to achieve them with maximum effectiveness.
After checking out that PUA stuff, it appears to me that the goals you call "questionable" are not grounded in rationality at all - it's all about not meeting the emotional needs of the women involved, and they mostly smell like men whose emotional needs have not been met by the prior women in their life (maybe even starting with their first woman, their mother). Lots of "popular" PUAs just seem vengeful to me, and I take that as a sign that it's their emotions that ultimately motivate them.
I think orangecat's point is that rationality and the moral correctness are distinct (assuming you haven't solved the is-ought problem). "Rationality" is just taking actions which are most likely to lead to your goal, whatever that goal may be.
Now, that still leaves us to explain the correlation between (a) rationality in the pursuit of relationships and (b) having "questionable" goals like pure sex rather than love. And I think it can be explained this way:
First, sex is a much easier to define and measure goal; it's hard to gather data about how well you have achieved ephemeral things like "love". This makes it less amenable to rational attack. Second, people who are initially rational are more likely to see the rather unpleasant realities of love (tracing it back to evolution-driven competition) and become cynical of even the existence of love (and so settle for sex). Third--and I think this is close to what you were getting at--men who have been shunned by women may become so bitter that they don't really want to the love of a woman while still acknowledging that they want sex.
Heh, true. And to the extent that we fail to achieve our goals with women and relationships, we're not being rational. http://lesswrong.com/lw/7i/rationality_is_systematized_winni...
You want rationality, look at pickup artists. They have (questionable at best) goals, and they do whatever it takes to achieve them with maximum effectiveness.