I think the assumption rose from the first scene where Sukuna said “where are the women? where are the children?” which would give some people first impression that he could be the R word.

at that time it’s fair, since we didn’t know a lot about Sukuna other than he’s a dangerous evil. but the more we got to know him, I personally believe that’s not the case at all. during above-mentioned scene, Sukuna continued with saying “It’ll be a massacre!” which we shouldn’t ignore, bcs it could have been simply about a massacre than the R. also we found out latter that Sukuna is a cannibal as he eats humans. Most likely he referred to those women and children as foods instead of, you know. he could be thinking about eating them in the most literal meaning.

We should also consider that all this time Sukuna has been called many things: The King of Curse, the calamity, the Disgraced One, but not once he’s called or even implied as a r*pist. The scene with Yorozu to me rather implied that he’s not interested in women in that way. furthermore, we had an example of how a character who was being implied as a r*pist (hint: Naoya) and Sukuna has never had the same implications so far.

But, there is also this scene with Sukuna commenting about Nobara, which some people use as a possible proof that he’s a r*pist. Unfortunately I forgot the exact words (he said about being active or what? I don’t remember) but I think Sukuna meant it not in that way, you know… (what a weak argument, if only I could remember Sukuna’s words in that scene).

anyway based on what I mentioned above, I personally believe he’s not a r*pist, but rather a mass-murderer and cannibal.