Different strokes for different folks, love her or hate her she gets crazy visibility to a demographic that may not have paid that much attention. The only way stuff like this gets changed is at the government level and the only way that happens is when you can whip the population into a fervor. I often ask some of these climate deniers whether they remember things like acid rain, holes in the ozones layer, or increases in environmental lead from gasoline and most either don't or only vaguely. These were all comparable world wide issues (presented by a consensus of scientists) that went through similar media cycles of people calling for action and being met with dismissal and claims that it was fake, overstated, not man made, etc. The reason you don't often hear about any of these anymore is because they were all addressed through governmental regulation. It should also be no surprise that the biggest and most funded pushback against every one of these was the corporations that profited from those emissions (in particular oil companies with leaded gasoline). This has not changed in the present day and energy companies don't function any differently. People seem more accepting of the fact that tobacco companies would try to manipulate citizens and politicians for their own ends than an oil company doing the exact same thing. Oil companies are so much worse because those roots run way deeper at every level of everything. Like tobacco companies have lobbyists but they are nothing compared to what oil companies can do. Going back to Greta, the amount of vitriol she gets from climate deniers is actually crazy. She is simultaneously considered a child who doesn't know anything and also held up as basically an avatar of climate scientists who spend decades in that field of research. Also crazy to see how much digging people will do to try and say she uses "too much" carbon and expect her to basically use nothing to get her message across. Besides the fact that's a fallacy of hypocrisy that doesn't affect the reality that her net impact on carbon use is likely to be far greater than the inconsequential amount of carbon she produces doing it.