Not at all; however, I have observed general libertarian disapproval for any disapproval of pornography.
Opposition to violation of individual liberties, by government or others, is a libertarian principle - and it's usually if not always governments that impose outside censorship, which is a violation of individual liberties. QED.
Don't give yourself too many pats on the back, you haven't actually demonstrated anything.
What most libertarians seem to fear more than anything is even the hint of opposition to their libertine depravity, the fact that government is authorized to curtail such depravity makes opposition to any and all government an underlying principle of libertarianism.
You and I must be seeing different samples of libertarians. I've seen a number of libertarians agree that certain acts are best avoided but nonetheless none of government's business. Some objections to "even the hint of opposition" may be in anticipation of a leap from 'it's bad' to 'it should be banned.'