Why do so many feminists seem to be anti-sex?

A curious mind asks:
Hello again. I have been dealing with an issue that I believe is rooted in religious morality. The issue is of being sex-positive.
Within some feminist circles, I sense reluctance if not outright disapproval about women who are proud of and enjoy their sexuality. To be honest, it feels as that if a woman were to really enjoy her sexual nature and beauty then she’s a traitor to feminism.
I resent that to the extreme. I don’t want to point out that men get to fully enjoy that aspect about themselves without any apology. I understand objectification and commodification of women, truly I do; however, I’ve seen some ultra-feminists shy away from sex-positive females if not outright condemn them.
I know I’m new to this group so I’d like to get a sense of what you all think…

It’s a very complicated issue.  First, feminists enjoy sex at the same rate as the population at large.  There are lesbians, straights, bisexuals, asexuals, all types.  They even use birth control and sometimes even make jokes about how they must be sluts as a result.  The fact that women are shamed for liking sex where men are shamed for not liking sex (and apparently all other genders are invisible) is sexism.  Feminism is against harmful gender-based double standards like that.

However, just because someone likes doing something doesn’t mean it’s good for gender equality as a whole.  Take for example the issue of posting nude photos of yourself online as a political act.  In Egypt, that can be quite a revolutionary statement against the male ownership of women’s bodies.  In the USA, if you think you’re being revolutionary, you’re a joke - we have no shortage of nude women and we never will.  Context.*  I mean, knock yourself out, there’s no shame in being proud of your body, but don’t assign political meaning to an act where there is none.

Which leads me to another thing that many feminists are critical of: the idea of sexual “empowerment”.  I have observed that there is a tendency to equate “empowering women” with “getting women to feel like pandering to the male gaze is something women do for each other and not for men”.  Protip: it’s called the male gaze for a reason.  And the reason it’s so frustrating (infuriating, even) is that there’s a decided lack of balance in society to celebrate other women’s choices to dress in sloppy clothes or swear off makeup or to (gasp!) dress in butch styles as “empowering women”.  Apparently it’s only worth celebrating if the hetero man-penis approves.

I’m sex-positive.  But it is so disappointing how many sex-positive blogs I read that embrace the above biases.  They claim to be about embracing the whole sexual person, but then they only focus on stories that pander to the male gaze.  Queer bodies aren’t represented.  Asexual experiences aren’t represented.  Monogamous couples barely get any notice except for those who practice extreme forms of BDSM.  Again, this isn’t all of them.  (I’d like to take the opporunity to encourage everyone to visit sexstl.org as an example of a group I admire.)  But when feminists see people take the patriarchy, wrap it in a pretty ribbon, and then try to sell it as sex-positivity, we feel cheated by the continual wasted opportunities for real progress.

*Someone has correctly pointed out that, even within the USA, certain bodies can be revolutionary that are traditionally marginalized by our society.