Support localism? Depends on to what degree. Do I support giving people a little $hit every once in a while when they do something really stupid? Why not...everyone has got some from an old timer over the years! Do I agree with harassing, threatening or injuring someone? Absolutely not. The bottom line is if you are new...know your place. If you are a local, or think you are (as it is in most cases), don't try to be a tough guy because even though you may surf well, there is a better than average chance you will get your ass completely kicked out of the water.
I agree, there is a certain point where "guidance" shouldn't pass. Teaching someone not to do stupid **** should not, and doesn't need to involve harassment or violence. Even if someone is new, you don't have the right to keep them from surfing, or making their time in the water miserable.