Let me preface this by saying that none of what I'm about to say is ship hate. There are ships I don't care for and kinks the squick me out but that doesn't mean you shouldn't ship them or have those kinks. I'll fight for anyone's right to create and partake in that content.
I have a degree in English lit and library science. What's happening within fandom right now is an extension of the centuries old argument about banning fiction because small groups of people find certain topics uncomfortable and think the world should cater to their feelings.
They want certain ships and content stomped out because it's "problematic". Here's what happens when they're successful as evidenced by history: once you start banning content, there is no end to it because all but the driest of fiction is offensive to someone.
My ship is problematic for some but guess what? In this fandom, so is pretty much every other ship on one level or another. I don't care if you think it's the cutest, purest uwu shit ever. Someone out there finds it morally offensive and can make a powerful case against it.
Is your ship angel/human? That angel is millennia old and the human is 35-40. That's a problematic extreme age difference AND a bonkers power imbalance. Plus non con bc the body they're using or face they're wearing wasn't given to them so they could have sex with humans.
Same goes for demon/human except that's even more non con since they steal bodies. Witch/human? Again, age difference with a side of off kilter power dynamics. Werewolf, shifter, vampire/human? All of the above plus maybe bestiality.
Has one member of your ship called the other his brother at some point? According to certain antis in other fandoms I noped out of, that means your ship is now incest. Congrats and welcome to the club.
Even human/human ship canon ships can be considered problematic at this point. Has one human died? Or both? Kinda necrophilia-ish then, dontcha know. Did the guy in question have his angel buddy tinker with the woman's brain without her consent? Yikes. Red flag.
If I was an asshole, I could literally go through every ship in this fandom and tell you why they are abhorrent and wrong and I could convince others of it because that's the one thing a lit degree teaches you: how to make a compelling argument for anything.
In short, purity policing is a worthless, pathetic pastime and a slippery fucking slope. The doxxing and death threats you're aiming at someone today could be just as easily turned around on you tomorrow. Stay in your lane, enjoy what you enjoy, and shut the fuck up.
And I'm not getting into the "my personal experiences mean you can't create this" vs "I use this content to cope bc of my personal experiences" debate bc no one needs a note from their fucking therapist to be allowed to enjoy something. Don't like it? Go on then, off you fuck.