I completely agree with the concerns about marketing. Yale University has been at the forefront of studying Climate Communication for years. As I have tried to explain the topics to students I have been very careful to listen to what their concerns are before taking further steps.
Like "used car salespeople" we need to listen with empathy to customer's desires. James Hansen, correctly understood the need to appeal to older voters as grandparents.
350.org and Greta Thunberg have much more of a in your face and confrontational approach. 350.org is currently pursuing a "purist" and "absolutist" response. Their science is correct but their marketing is problematic.
The goal for Democrats should be the largest possible "tsunami of Blue" in 2020. That is accomplished by having a moderate and inclusive platform while working as quickly as possible at real solutions to climate change that will enlist support among young and Republicans and responsible business leaders.
End and means must pull together or we will be paving the way for the next Trumpian slowdown on effective climate action.