I didn't think that such activities were illegal.
But what you did might be a crime; it depends on what the law is in Mass.!
“When in those towns I routinely tear down posters from telephone poles,etc that espouse various Maoist policies.”
Back in the mid 80’s, a number of College Republicans (yes, I was one of them) were given these stickers that said KGB APPROVED. We’d stick them on various leftist posters that were placed on campus.
Inevitably, some offended student would try to peel off the sticker and ruin or rip the poster.
That was cool.
I think these were on private property.