You've got little concept of what their cause is. Their cause is "you've pushed us to the breaking point and this society is no longer worth enabling, the social contract is dead." It's not to make the liberals sad, it's to hit everyone who wants to enable the system through disruption until their grievances are acknowledged. That's always been the method of even the most peaceful of successful protest movements. The entire point is to flex political power(and I'm not talking about voting here), not hope some liberal gives them thoughts and prayers.