It's a different way of saying "beat the shit out of", which means you hit someone really hard. Informal and also the word shit or shitter is considered vulgar.

Oh thank you :) Now I fully understand. But there's one thing left so confusing. what is the meaning of "shitter out of"? Especially, I don't get the meaning of "shitter"😀

It's vulgar. It's saying that women beating up men is now normal (presumably in films or video games, rather than in life.) If I had to "read" it, I'd suggest that the writer is trying to display his (I assume this was a guy), or maybe her, high level of "cool", claiming that he is on top of recent trends in games or movies so he is in a postion to pronounce on what is "corny" - done too often to be interesting. I'm not in a position to say whether it's sexism for sure - I think I'd defer to a woman on that . It might be. https://www.urbandictionary.com/define.php?term=corny https://dictionary.cambridge.org/dictionary/english/corny