We all want to ban something. It is a staple of our political culture. All of us are perhaps one moment away from seeking to ban what someone else is saying or doing. The nod-a-long responses of "it shouldn't be allowed" or "there should be a law against it" are the common solutions to many perceived problems.
However, to "ban" something is not actually to eliminate it, whatever "it" is. The "it" is not extinguished; the "it" may just be attended by some different consequences. The legalistic prose in a solemn document is not some magic spell which banishes horrors by invocation. To say there should be a law against a thing is often no more than saying there should be a spell against it.
In fact, "banning" things often creates new problems. In its correct legal form, a prohibition establishes certain legal and coercive consequences should the prohibited act occur: a court order for damages, say, or a prison sentence. Being banned does not thereby stop the thing from happening. It just means that the legal system will be engaged in a way it otherwise would not be.
Now, he's talking about "bans" and not "banns," which are the posting of the announcement of an upcoming marriage. Some people might say that "banns" mean also mean all sort of things are now banned as well, a number of them a lot of fun, but that's a discussion for another day.