A movement can have members and leaders even without formal organizational hierarchy. It just won’t look the same as something like a corporation, nonprofit, or government. The person who noticed that the Proud Boys were coming to town and rallied people to a counter-protest? Definitely a leader. The people who show up on a cold rainy Saturday instead of staying indoors with a warm cup of tea? Members. Just because membership and leadership is more amorphous doesn’t mean it isn’t there in some form.