I don't know of many libertarians (or even Libertarians) who would deny that there are social consequences to pornography. I suspect that most feel as I do on the subject.
Those who engage in obsessive viewing of pornography, and those who marry porn addicts are suffering the consequences of their own choices. While it would be nice to wave a magic wand and save people from the consequences of their bad decisions, some problems are probably insoluble without creating worse issues and side effects. People are often self-destructive, and we can't cocoon everyone indefinitely from actions that have consequences. If it's not porn, it could be gambling, drugs, alcohol, risky stock market investments, sub-prime variable rate mortgages, risky sex, fast driving, riding a motorcycle without a helmet, free solo climbing, choosing the wrong life partner, gaming addiction, and/or under-insuring. The people who seem to me to be most vulnerable to porn addiction are those with poor impulse control, and addictive personalities, and I for one would rather they look be able at their filth on the Internet than resort to hiding wireless cameras in ladies rest rooms, or over motel beds.
I do support formation of a .xxx top level domain in the hopes that porn will self-segregate their and be easier to filter. However, the US Gov't is against it. I also support the idea of harsh penalties against malware and trojan software developers who infect people's systems with porno-popups.
as are so called "Moral Groups" such as Focus on the Family ... belying their BS line of protecting children and showing that they really want to legislate and control the actions of adults ...
And freedom, by itself, is no virtue -- it is necessary for full human development, but there are aspects of being that are both necessary and virtuous. Like responsibility.
If a culture encounters a new thing, a change in the ground so to speak, such as gin in England, or the bottled booze industry in the US, or in our time, porn on the internet -- it is sometimes a necessity to implement social circuit breakers that do lessen liberty, if considered by themselves alone, so as to rescue the unadapted culture, the culture without-as-yet developed barriers and protections from the tyrannies of addiction and destructive behaviors that the "new thing" brings on.
These circuit breakers are a temporary thing -- if not, then they are Mohammedean afflictions to freedom.
The human body can fight of a germ -- yet if a person gets a fever and is overwhelmed by weakness and ill-feeling from the propagation of the germ, that person both withdraws from the full freedom of daily activity in order to rest and recover, and also takes a bitter medicine -- an anti-biotic -- to stop the infection, as well as other medicines to ameliorate the negative effects.