Freedom of Assembly
It is our right as citizens to gather with like-minded people to discuss and advance social causes. It's necessary, in fact, for national progress. Outmoded ideas must be discarded or adopted to meet the needs of a changing world.
It is also our right to peacefully demonstrate. The Supreme Court has confirmed multiple times that gathering to express a social or public opinion is protected free speech.
Minors cannot vote, but the power of their energy and idealism cannot be denied.