Well, ok. Got your point. Porn had existed since before Roman times, e.g. Pompeii, which was an R&R center, had porn on the city walls. The Greeks liked young boys etc. Showering with classmates after rugby in my youth was accepted and there was no shame in seeing naked bodies.
However, whereas pedophilia was more accepted in history, society has moved away from it. People associate children watching porn with nascent moral corruption. I don't agree, as you, that it has a huge effect but I haven't seen any research on it yet