On a more practical level, it can be counter productive to the protester’s cause though. I used to work at a busy convenience store in a city where I would talk to many people throughout the day about what was going on in town, including one day when a small group of protesters shut down the major freeway in the area. It only turned the majority opinion against them and increased support for police. Literally no one so much as even mentioned what they were protesting about, let alone gaining support