Explaining slut shaming

Slut shaming is the act of mocking somebody, usually female, for being overly promiscuous or sexual. In other words, it's shaming girls for having a lot of sex. It's fucked up for sure. Although it should be noted that women do it just as much, if not more, than men do. Which makes the sexism claim about it a little suspicious. That claim becomes more understandable when you compare slut shaming to how men are treated for the same sexual behavior. Unlike girls, guys are praised for having a lot of sex. That double standard is how most people explain how slut shaming is sexist. Im here to tell you that it's not. It is natural behavior that has its roots in ancestral behavior. Basically, think of girls as locks. Think of guys as keys. A good lock doesn't get opened by many keys, but a good key opens many locks. This is why slut shaming is natural. Females' biological role is to choose the best mate. Best mate being the one with the genetics that make up a higher survivability rate. Choosing many to mate with indicates low standards. Males' biological role is to mate with as many females as possible. This indicates a good genetic makeup. Again, a good genetic makeup indicates a high survivability rate. That's the ultimate goal here. This is pretty primordial thinking and doesn't apply so much in the modern day. Which is why we are starting to see it as wrong. It's no longer useful for our survival.
A common rebuttal to the lock and key analagy is retarded. I will inform you of it then explain why it betrays a complete lack of understanding the lock and key analagy to begin with. Here it is "A pencil that gets sharpened too much is eventually reduced to nothing. A pencil sharpener can sharpen tons of pencils and be just fine.". This is the dumbest rebuttal to an argument I have ever seen bar Trump's trademark wrongs. The idea here is that they can make an analagy that makes just as much sense but portrays men as the bad ones. The problem here is that the lock and key analagy isn't there to portray women as bad, its there to explain biological behaviour!!!! It is biological fact that this is why slut shaming exists. That doesn't make it right. That doesn't make it wrong. It just is. The pencil-pencil sharpener analogy has no basis in any form of biology. It does not have it's roots in any form of factual analysis. Why critics of the lock and key analagy spout this as if they are Debunking something is beyond me. They clearly do not understand the point of the lock and key analogy. That point being biology. Just because you don't like the explanation for something's existence, that doesn't make the explanation wrong.