[haswell]

The potential downsides associated alcohol consumption are well understood, and this understanding has permeated most societies.

The same cannot be said for porn consumption. While studies exist, this is not a well understood topic, and big claims are going to be met with skepticism and demands for evidence.

[Spooky23]

That makes sense, as alcohol use and abuse has been with us for a millennia or more. The internet is a tad bit newer.

If you look, you will find plenty of inquiry, debate and research into the topic.