If the writer sees the warning from "...pundits on Twitter" that the march would mean nothing if the events of were not turned into concrete action as "on-line negativity" the movement (or, whatever it is) is in trouble. It's good the writer admits the statement's truth.  So many marchers had such disparate reasons for marching--not a good sign. Where's the solidarity? Let's put this multi-city, multi-country protest in perspective.  

Just seven years ago, perhaps the world's largest cohesive street demonstrations occurred in the middle east. Major protests in 8 countries involving millions. THAT was easy--thanks to social media.  Some small success--some governmental changes and resignations, replaced by new despots. Result: 3 civil wars (Syria, Iraq, Libya), hundreds of thousands dead and little permanent positive change. 

 Why? Because protesters couldn't organize beyond their demonstrations. It's what's done OFF the streets that counts. For more, read Homo Deus, by Yuval Harari.