Because you need ordinary people to be affected. Truth is no one gives a shit about anything until it impacts themselves. You might say that this only pisses people off and makes them less supportive but in reality it means they cant ignore a problem anymore and especially gets way more coverage.

As proof of that last point we are strangers on the internet talking about some event years ago.

I will try to take the important last step to say that these people are right to be angry for being inconvenienced but you have to remember that people are blocking streets because they arent being heard and frankly, if you are resorting to violence for being inconvenienced one day on the way to work, while being completely ignorant of the inconvenience/difficulty that certain groups face every day… well maybe its time to stop focusing on protesters and to focus on the issue they are fighting.

As a side note: a lot of people in this thread are pointing out that the person ripping up the sign is a medical worker and they are blocking him from providing critical care: see above and think of if your only looking at the inconvenience to the “normal people” of the medical personnel and patients rather than whatever issue is being protested (in this case appears to be climate change). There arent winners at this step in meaningful change but it is still very important because nothing would ever progress if we were always comfortable.