I'm not saying horror can't be paired with other genres. I'm saying that if you're doing a story based on a genre...you should still have that genre in there. Ok, I shouldn't forget that the horror is there. Or that the romance is there. Or that whatever else.
Tags or not aside, I'm going back to my main point that NSFW and Ecchi shouldn't overtake the story if you're trying to sell a serious story and you gave your readers that idea that it wouldn't overtake the story.
If you're not trying to tell a serious story and you want it to be in your face? Fine -- that's a different story.
But if you're trying to give me something that's not just ecchi (horror or thriller or whatever)...I need more context than just ecchi. Don't just throw boobs at my face and think I won't notice. I mean, boobs are nice, but that's not all I came to read/watch for because that's not all you were trying to sell me.
Just...I know I'm ranting, but I really would rather peeps be upfront and go "yeah, let's do sex but in space or sex but in a zombie invasion" than say "this is a serious crime thriller about the mob corruption in downtown Los Angeles" but all I see are the detectives hanging out around the brothels. Just...be upfront 
I don't care about seeing NSFW. I AM a NSFW artist. Just, don't lie to me and tell me your story is something else when it's not.