Sure, I can see that for an asexual person it may feel oppressive to be surrounded by sexual imagery.

To begin with the items you've mentioned:

Sex can be used to increase social standing in many ways. Having sex can also be an opportunity to form strong emotional bonds with someone or more nefarious bonds as in the case of blackmail. Furthermore, if the person one has sex with is important, that can confer social standing by association. For example, Michelle Obama is important because she had sex with, married and had children with Barack Obama, who is of course, the current president of the U.S. Thus, she has a high social status. When Obama is no longer president, it is likely that Michelle Obama's social status will decrease as well.

Also, being considered sexually attractive is in itself a form of power over those who would wish to have intercourse with that sexually attractive person. It might not be power in the conventional sense. Think of it as "soft power." For example, Kim Kardashian isn't anyone of any real importance. However, she is considered physically attractive and has been able to attach herself to various people to climb socially and thus gain money and exposure, which in the culture she lives in, equates to power. With power, comes social status and often vice versa.

As for stress, well, the need for sex is different than the need for other things. In part, it's because it's very closely bound with other human needs, like social interaction and touch. Also, sex is different things for all people, so my sexual needs are not your sexual needs and your sexual needs are not Kim Kardashian's (as far as I know).

Another thing to consider, is that sex is much more than sexual intercourse, it is a social interaction that is as much mental as it is physical. That you can't relate to the pleasure of sex means that necessarily, you will have a lesser understanding of sex since pleasure is what colors every one of the items listed.