I’m going to play the devil’s advocate here and say that Itch.io should only remove strictly illegal games rather than setting a vague arbitrary line that seems reasonable at a glance. I don’t think it is Itch.io’s responsibility to cherry-pick out which games are morally wrong or socially acceptable since it is impossible to satisfy everyone. There are countless extremely successful fiction works that would be banned under the label of sexual abuse, Fifty Shades of Grey is the best example. People will say that Fifty Shades is encouraging sexual abuse, even if the protagonist willingly agrees to the seemingly abusive sexual interactions that take place there.
Censorship crusaders will go on a field day if an arbitrary rule is set, even if the rule is only meant to stop the worse offenders. Sexual objectification? Well, they can argue that showing female characters in any garb that doesn’t cover up to the ankles, or female characters having body proportions other than a potato (hourglass figure, unrealistically large breasts) is the sexual objectification of women and then there goes 80% of games on here. If a game plot involves saving the girl, it will also be considered objectification because “they’re treating the girl as a prize” and poof there goes Super Mario Bros. You may think I’m being unreasonable, but just taking a quick look at various Twitter dramas about video games would hopefully convince you otherwise.
Setting the threshold for acceptable content on a large platform such as Itch.io is not trivial. But I could make a few suggestions. First is the Newgrounds blamming system. Bad submissions get blammed by users and enough blams will depublish the submission and the creator has to revise their content before resubmitting. The second is adding another rating on top of the mature rating for games with extreme content, but I think this is better discussed in the main discussion thread. Lastly is implementing a default tag exclusion in search and main page listings. People who do not want to see certain tags can set this on their profile page and never see games tagged with them ever again on Itch.
Mature games are meant for mature audiences only, and as adults, we all have the choice of not playing a game if we don’t like it. The only complaint I have is the annoyingly explicit cover pages for these games being shoved in my face (maybe a better cover page policy?)
Edit: I forgot to mention why I used sexual objectification, it’s because OP’s previous linked post included the call for banning content with sexism, and they quoted the sexism definition on the wiki that included objectification. Ergo they are also advocating for the removal of games with sexual objectification.