Because it takes far more effort to carefully rebut a slur than it does to make it, and if you let it stands as is, you've lent it credibility. We all intuitively understand this, which is why overt arguments in favor of crimes against children (which arguments do occur!) are instantly flagged off the site; we don't entertain them or carefully rebut them, and practically no one on the site expects us to. It's just that a noisome faction on the site does expect us to entertain slurs against women.

For a similar example in a different site, see https://slate.com/technology/2018/07/the-askhistorians-subre...

“In this endeavor, deniers focus on many minor and obscure details and leave out crucial context. It takes them little effort to formulate a wrong assertion, but it takes historians a long time and a lot of words to refute one. Our early attempts to engage on these points have shown that length and nuance do not play well on the internet and do not interest the deniers. The point of JAQing off is not to debate facts. It’s to have an audience hear denialist lies in the first place. Allowing their talking points to stand in public helps sow the seeds of doubt, even if only to one person in 10,000.”

like i said in another comment:

`As those claims often are not really evidence-based, seems to always target the same group and have unhealthy proponent, i might dismiss them a sexist, even if the author is in good faith and wants to understand why people dismiss his point. `

I'm not saying i'd downvote everything, but this is tiresome. Have a basic understanding on how genome works is really easy, you have free courses all over the internet and you only need ~2 hours of genetic 101 to understand than any biologic/genetic "fact" based on sociology, statistics and questionnaires and NO physiologic evidence at all is just dumb, unhelpful and uninteresting.

[edit] And if it's uninteresting and agressive, it should be downvoted.

"What can be asserted without evidence can also be dismissed without evidence"

Hitchens

There's nothing to engage with there, it's just not an interesting argument. There's a huge difference between just having a different opinion than most whilst still being able to defend it, vs. just $#!+posting like that flagged commenter did.

It's not true, you are just overgeneralizing your personal opinion on what is interesting as if everyone should feel the same way. Other people might disagree and find it interesting to discuss for whatever reason, even without original poster defending his ideas, maybe it can serve as a gateway to go deeper into the topic and make it interesting even for you, while you think calling it shitposting is ok.

In my mind flagging is the right behavior for what amounts to ideology spamming.