demonstrations with signs and chants in the street are the simplest form of protest and ideally would be the only one necessary. if they're not backed-up by the threat of more disruptive and direct action, they're toothless and ineffective. protesting is the whole thing, and since the power systems don't usually give a shit to the first and kinder stages of protesting, it becomes necessary to venture into the realm of "cRiMe"

the definition of crime is arbitrary and subject to change and not really relevant to the definition of protest

Nope. Also not what you said.