things some people, especially people who are new to ao3 or fandom/fanfic space as a whole, seem to not understand:
archive of our own is an archive. not a social media.
archive of our own was built with the stance that there would be no censorship, because other platforms already had censorship where some things that were taboo were reported/removed. ao3 was built with the purpose that all of these works, that were not allowed on other platforms, would be allowed on ao3.
the archive will house anything that’s considered fanworks. so no, you cannot report this fic because it portrays in explicit details taboo topics about xyz, you cannot report that fic because it romanticizes and glorifies xyz. ao3 will not remove any of those fics, because whether or not you like it, those fics do not go against ao3’s terms of service.
“but these things are not allowed on other platforms” that’s precisely why ao3 was created, to house and give a platform to these things that were censored/banned/removed from other platforms.
if you have a problem with this, you can use other platforms to post and read fanfics
but you should also know that ao3 by far has the best tagging system, meaning you won’t get anything like what ao3 provides on other platforms, meaning it may be a pain in the ass for you to find a fic with the prompts and pairing you’re looking for, meaning you may still get jump scared by things that are triggering to you half way through your reading of what you thought was an innocent fic. because other platforms don’t have tagging systems, where you can find and avoid any character/pairing/tag as you please, like ao3.