Vandalism is defined as an action involving deliberate destruction of or damage to public or private property. If at all this changes were not initiated by the management of the sign then it is an act of vandalism. The Los Angeles police should investigate and arrest the those who defaced the sign.
Does reporting on murder increase killing? Does covering a bank robbery increase the likelihood people will rob banks? Nope. It's just the media doing their job, and sometimes things get more coverage than others. It doesn't mean more people are going to go out and do the things they see on TV or in the news.
With all of the terrible things that happened in 2016, there is nothing wrong with reporting on the Hollyweed sign. It is something that is just funny and silly. Nobody died. Nobody got hurt. It didn't take long to restore. It was just a harmless prank. That is what pranks should be.
People have been messing with the "Hollywood" sign forever, even before the days of widespread internet reporting. I think it's sort of a tradition to mess with the sign. Reporting on the issue gives it more coverage for sure, but I doubt that it's going to convince anybody to mess with the sign that wasn't already inclined.