I can go door to door asking people to change something, and dozens of my volunteers will feel useful but overwhelmed by how much work there is to do in a city of a million people. Or I can go to city council meetings, and get more leverage there. Or if I can convince one high profile citizen to participate, others will follow. Or I can get into contact with the mayor, state congressional members, the governor, federal congressional members.
It's possible that if I convince the correct five people that they will take half of this burden off of my hands. You'd be crazy not to reach for a lever like that. They are a juicy target, and not just from a punitive standpoint. Of course when you are rebuffed repeatedly by a potential ally, then it's a very human (if questionable) response to seek out some sort of punishment.
edit: What I mean to say is, people have been organizing against FB, AMZN, and tech in general for the past few years now. The last is reactionary but opposition to FB and AMZN has meaningful academia, ngo/gov, and general support.
But... that group wouldn't be able to do nearly what it has if it weren't for funding from foundations and the department of neighborhoods, and resources on permanent loan from another public sector organization. You might argue it couldn't exist at all.
I think I would say that both are necessary but insufficient.
edit: https://qz.com/1704143/the-antitrust-case-against-facebook/