You guys don't "express unhappiness with an American policy", at least not anymore. You throw violent, adult-sized temper tantrums where people are injured, property is destroyed and commerce is interrupted. Not to mention, it's fucking endless. I mean, yeah, we get it. You're pissed off about something or other. Now get the hell out of the middle of the road so I can get to work and pay for your free shit. And by the way, if I run you over and snap your spine with my truck, then no, I don't think you should be prosecuted. Hopefully that would be a life lesson.
If someone is injured or someone else's property is damaged, that is a crime and is actionable. Protesting and speaking out, no matter how upset it makes you and no matter how often I do it, is my right.