It would appear to me that YOU need the lesson. No one prevented her from speaking, however we too have that right, no matter what you may think, or understand.
Saying "Cindy, you are wrong." or "Cindy, you do not speak for us." is one thing but, chanting "Cindy, Go Home." is telling her to 'shut-up' thus denying her her Freedom of Speech. Perhaps, chanting something about the successes of the War would be more Appropriate.