For the use of the rape word, I think it is a more complicated question. It just goes back to the universal variable, extremely present in the english speaking internet community even if it's something probably universal on the internet (in my opinion), which is minimalizing the strong meaning behind some very vulgar slangs, "fuck" being the first one to come in mind, or like in the eve community "ass rape", "rape train", "stfu", "htfu", or even "it's gay" or the extremely offensive misogynist "you don't have balls / he had the balls to do that", or whatever. Everything then tends to quickly get into hyperboles to express a feeling or a thought, which means that people will usually tend to use stronger, violent, connoted words to express the same feelings that could have been expressed with more moderate, peaceful words. It does not mean that people are themselves violent, disgusting, or else (even if a lot of them actually are but that's just my misanthropic side speaking), it just means that they do it unconsciously because everyone did it and lessened somehow the bearing of these words/phrasings.
Often too, it can be used in a funny way actually meant to make all these strong things a lot more bearable, when taken with a smile (in a positive way). It somewhat a double edged sword to my eyes, but well...
Overall on this topic in particular, I have already reported a significant amount of posts containing that kind of slang that I consider sexually offensive or violent, and that contribute to my opinion to an oppressive atmosphere where I feel surrounded by intense, aggressive words and phrasings. The reported posts never really got moderated, which might point at cultural differences or just a thin skin on my behalf, I honestly don't know. But I am quite weary of the use of that kind of words every time for everything.
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For the offensive images in spoiler tags somehow not being moderated, I didn't notice in the first place but I agree, so why not reporting it in the first place ?