Your theory doesn't hold a lot of water, since (off the top of my head) I don't think there's been any sharp decrease in the number of sexual assaults when VHS was released (late 70s/early 80s), or during the dot com bubble (late 90s), in any country. The porn industry was behind a lot of the push for VHS because hey, they saw a far better opportunity to sell their wares because obviously people would prefer to watch that kind of shit in the privacy of their own homes, and likewise with the internet adding an extra degree of privacy and more widespread availability/advertising. In fact, in Australia, which generally speaking has little to no censorship, records of sexual assault have been on the rise since at least the early 90s (I just can't be fucked making an effort to look up more stats on the subject from before that time period). So yeah.
Also I think the whole idea is fucking ridiculous to begin with.