Unlike obscenity though, there is at least a universal consensus on what constitutes murder, and what the justifiable defenses are (e.g. self-defense).
Secondly, murder is codified in every statute and the Model Penal Code broken down by degrees and the elements for each crime. Further, there's other related crimes (reckless injury, manslaughter, etc.) that may also fit the bill.
Our point is that while we may agree that obscene stuff is harmful, nothing can be done about it until we as a society figure out what constitutes obscenity. Then we can begin to create standards, laws, etc. around that definition.
if enough people cared, similar definitions could be made for porn. just like every non-natural death is not premeditated homicide, there are various degrees of porn
more could be done to discourage porn. a lot could be done by private individuals, groups, and companies, if we were free from government forcing us to be "morally neutral" how we could enforce a social stigma.
Much better stated than I could have done.
We already agreed on those definitions and principles at the founding of this Country. The Ten Commandments have not been rescinded. They have 'only' been eclipsed by a penumbra here and there.
Time for the sun to shine again.