As far as I can see, as a technicality, necro is no more illegal than bestiality in general. I did see a case of where a guy got caught taking advantage of a dead deer; he made a novel argument that the animal was no longer a deer, but meat, as it was dead. Iirc he lost that argument, but the pretzel logic of the laws just defy rational thought.
If anti-beast laws are really intended to "protect animals from sexual abuse", how can that extend to protecting a corpse which is not sentient, and is indeed basically just meat? I think the guy had a point. But the law is going to find a way to punish someone for what it perceives to be "shocking or disturbing behavior" whether it's technically and expressly illegal or not.
That said, that particular individual has some real problems, he was also convicted of killing a horse bc he wanted to have sex with her. That is just the absolute worst imo. I think most would agree. I'd happily throttle the guy if I encountered him.
I dunno. I like deer. Lots of people do. Given the option, I have no doubt that a huge majority of deer-fanciers would vastly prefer having sex with a live one over a dead one. It's not so much they like necro per se, but live ones are near impossible to interact with on any level, much less getting frisky with.
It's hard to even find good quality photos that show their genitals in any detail. I'm sure they have been taken, but normies discard such photos as "ruined" and certainly won't post them. People are embarrassed and/or repulsed by themselves and by extension, all animal reproductive organs. Somebody will post a photo that includes their dog's testicles in all their glory- next thing you know they're being admonished to neuter their dog. Why, so you don't feel tingly when you see them swing? Anyway, I digress.
The tricky part becomes determining origin and intent. Ok, so here we have some dude sexing up a corpse of whatever. What caused its death? Did he kill it just to have sex with it? I think everyone here can agree that is the ultimate abuse and is wrong, and it shouldn't be permitted. But how does one know? I've seen deer necro on zoox. Some seemed to be obvious roadkill, but others- did the guy shoot them? Maybe he did. Then- Is it wrong for him to fuck his prize before he butchers it? I honestly can't see the harm in that.
As evidenced by that one guy example above, there are guys that would kill something just to have sex with it. But I think that is one rare case and shouldn't be used as a fair representation of what is happening in almost all necro videos. The ones I've seen look to be usually roadkill, and a few cases of possibly hunted.
If someone is causing no harm by having sex with something, is that harmful to anyone? Should it be banned just on the merits of "that's gross" or "I would never do that!"? I don't visit the scat thread, not my thing. Fine by me that some like it, who am I to judge?