> What if the victims of the sex crime are dead (of natural causes)?

Still ok to ban it. Clearly I am putting pornography in a different category from other forms of images and 'speech' but I'm comfortable doing so.

> How about non-reporters using murder footage for some dumb purpose like background footage to their halloween album?

Fine.

> You can draw reasonable lines, but it's in a very different place from "depicts a crime yes/no".

I agree. Depicting crimes isn't the problem, there's the issue of preventing incitement and blocking avenues for funding criminal activities. Pornography is so particularly and differently vulnerable to these abuses that I think special treatment under the law is reasonable.