> The sunset of Christianity's influence in the west has just as much to do with it.
What a common lark, and yet completely false.
Look at China - pornography is illegal. Guess what the firewall is also censoring. They are a completely atheist government by policy.
Look at India - pornography is illegal to distribute, and even though it is legal to privately consume, violent pornography is just as illegal as child pornography for private consumption. They are also not a Christian society.
Look at any Islamic country - be it Iran, Saudi Arabia, Afghanistan, etc. You'll be lucky to save your head if you get caught publicly using it. (Of course, privately, there's a lot of users - but that's useful for blackmail.)
Look at Japan - pornography is legal, but all genitalia must be censored or blurred.
Look at most of Africa - pornography is illegal and heavily restricted, despite their Christian status being tentative at best.
Ironically, post-Christian countries are the only countries where this stuff is legal and unregulated as it is. Believe me as well, as Islam gets stronger in this country, you might be surprised where the strongest opposition starts coming from.