So the entire argument is that adding, altering, or removing something from private property without permission is violence? I don't really see how. Since "the argument could be easily made that indirectly it can and does cause harm", I'd love to hear that argument.
My argument is "defacing property is an act of violence." "Defacing" by definition is alteration without permission, whether by act of adding of removing some feature.
Definition of Violent Knocking someone out is violent. Stabbing someone is violent. Setting off a bomb in a crowded area is horrifically violent. Defacing property is petty and disrespectful, but it is not, by any definition of the word, violent.
via Merriam-Webster Online Petty violence perhaps, but yes, defacing property is an act of violence.violent: using or involving the use of physical force to cause harm or damage to someone or something