Calling incest "taboo" when it's a literal form of abuse is not the wording I would use to defend its presence or people's interest in it on a site.
I use the word "taboo" because I only refer to "fiction", as in a taboo topic people write about in fiction. not real-life. fiction.
game of thrones has incest in it (so it is in a way taboo). and it is allowed to exist on a huge platform like hbo, because it's fiction and taboo fiction is NOT a crime.
lolita is taboo, but it's fiction, and it deserves to exist without being banned or censored.
non-con fics are taboo. because while it is vile and a crime in real life, just like incest, in fiction space where no one in real life is harmed, it is not a crime and it's legally allowed to exist and have a platform like ao3.
also no, I am not "defending the portrayal of taboo topics in fiction" even though I do love writing and reading about non-con. I am defending people's rights and freedom to create and consume whatever they want, however they want, including dark and taboo topics. as long as no one in real life is harmed.
thoughtcrimes are not real. and censorship is a fascist tool. period.