IMO, the views that rational analysis and manipulation in social context (esp. with regard to mating) is immoral or dehumanizing is based on observations that a lot of people who consciously employ such techniques often have the wrong objective function.

Consider this analogue situation: If you raise children, you definitely do a lot of rational thinking about their needs, long term interests and try help them to develop, be safe, etc. This requires a lot of objective considerations, prioritizing, even conscious manipulations on several different levels. Nobody would say that this is wrong, dehumanizing or out of place. The reason that this is intuitively accepted is that you probably do this for the right reason: in the long term interest of your children. If you have the right objective function, it is not just fine, it is required.

I think that other social interactions should not be different in this respect. You should consciously employ techniques, objectively analyze and manipulate situations, but your objective function should include the interests of your peers as well. They will sense if you genuinely care about them: Even if you manipulate them, they will be still thankful later if it happened in their long term interests.

You don't become a "manipulative bastard" just because you are manipulative, but if you are also a bastard.