Some thoughts:

- What do you think about violence in games and video? Violence is probably just as primal as sex, and I think most of what you say could be applied to violent media. Normalization of violence? 10-year-olds seeing extreme acts of violence and thinking obsessively about them? Energy and creativity being spent on violent games? Exploiting game programmers (I'm not kidding here, there's quite a reputation for long hours, low pay, and burnout)?

- maybe porn can reduce the amount of rapes and non-conforming sexual acts, but those should be considered morally wrong anyway and guided towards educating our children to restraining their urges towards that anyway. I think almost everyone learns that rape is immoral. A small fraction of people either don't care about morals, find some moral excuse for what they want to do, or have some kind of compulsion. For those who don't care, I think there is evidence that (at least some) psychopathy is caused by certain parts of the brain just not not working; about moral excuses, I would guess it takes the form "they deserve it" (some perceived injustice) or possibly "they will or should end up enjoying it"; compulsions are compulsions. I don't think there is reason to think that more education is likely to help. Some people resort to chemical castration of sex offenders, presumably because nothing else has seemed very effective.

- Many specific complaints don't apply to particular kinds of porn. Consider an exhibitionist young woman who takes pictures or video of herself stripping and masturbating, and posts it on a free site. There's no gagging, violence, impossible beauty standard (assuming it's a relatively average young woman), no comparing oneself to the actor (assuming the consumer is male), no taking advantage of people.

If the objection is specifically that some things are too extreme for young people to see (you mention 5-10 year olds here), well, fair enough. Films can get rated "R" for violence, too. Not that age is the universal metric, though; there are 10-year-olds who can watch a bloody stabbing and 20-year-olds who can't. (Also, people's ideas of what children can handle are kind of screwy. Hansel and Gretel, a tale for children, contains: attempted cannibalism, attempted murder of children (including abandoning one's own children to die in the woods), and burning someone to death. Thanks to Asimov for pointing this out.) To that, I'd mainly recommend good and not-misleading labeling of things.

In fact, if you want to minimize the chance that twelve-year-old boys end up accidentally watching extreme porn, then a good way to do that would seem to be to create a very popular porn site that has only nice, vanilla, missionary-position sex between consenting adults (or whatever)—or which puts all its more extreme stuff in an area labeled "extreme" or some such. I would say something resembling this is done to a limited extent: Pornhub in particular says they don't allow "rape, snuff, torture, death, violence". Perhaps you'd prefer the "default offering" to be much more vanilla than that.

But it sounds like you also object to adults having unlimited access to porn. Well... I'm just going to disagree there: I think it helps people sublimate unfulfilled sex urges in a harmless way; and if one group of people peacefully decide to use a camera they own to produce data that they peacefully provide to others, then I don't like the idea of laws preventing that.

Regarding addiction, I don't think most addicts to, say, alcohol would advocate that everyone should be prevented from accessing it, even if that would make it easier for them to stay off of it.