Anyone who dismisses a person’s comments based on that person’s age is a counter revolutionary.
Whether that person is younger or older by out-of-hand dismissing them based on the date of their birth may be denying the revolution a valuable contribution, just as belittling the contributions of women or people of color has handicapped movements of the past. Disagree over politics, ethics, tactics, but if you try to invalidate someone based on skin tone, gender, age, orientation, accent, physical abilities or any other attribute of theirs that has nothing to do with the content of their character you are not a revolutionary, progressive, or even an ally. You’re just another myopic asshole working for the other side without knowing it.
You are also, importantly, probably a hypocrite. Seriously. Look in a mirror. Whatever sort of person you see could be invalidated. For instance if you see a “progressive” young White woman in your mirror who invalidates people based on their age why should I, a Black man, use a similar reasoning with regards to your opinions? I mean, White people in general are much more dangerous to me than old people.
The point is we need to find and cherish our allies, not exclude people in the same narrow-minded way our enemies do.