Perhaps it has more to do with the way the Arts Walk has become an orgy of highly intoxicated 19-year-olds with little-to-no actual interest in the art itself.
Regardless of whether you like the art or agree with its message, you don't vandalize. This controversial artist uses his work to get his message out, why don't those opposed to him do the same? That seems like a far more constructive and logical solution.
Graffiti is art, even when it's done to private property, but smashing a window is bad?
Vandalism is vandalism.