Then why did you say this?
Is it wrong, just for those who are Christian, or is it wrong for every single human being everywhere?
Depends on what you mean by "Free will." Do you think it is okay to make anything illegal on the basis that it is morally wrong? For example, murder?
As christians we are called to live to God's standards. Therefore WE do what is expected of us. Others? They have no such moral restriction on their behavior. Sure there are laws regulating some things, but those are obvious. Do not kill, rape, steal, whatever, those are cores of behavior. And its very irresponsible trying to win an argument by comparing porn to murder in your search for answers. The two are nowhere near each other. One permanently ends someones life and the other is filming of a sex act. Two completely different levels of acts. Besides murder isnt always wrong but then we have caveats for that. Also, the majority of humanity would probably say murder is wrong regardless of what religion they follow or not, porn on the otherhand, you probably wont be nearly as successful at.
Besides making things illegal doesnt stop them...drugs, murder, prostitution, prohibition....so instead of regulating porn as the government has some hand in now, you have made it illegal and therefore devoid of restrictions, allowing quite possibly worse material than what there is now.