She is a rich girl.The autism is unfortunate but she is obviously a very bright individual and it certainly won't deny her a wonderful existence.Her message is great but i just see her entire story as somewhat manufactured to champion the cause.Manipulation springs to mind.
In wrestling fan circles we call this "cheap heat". Cheap heat is such a wonderful concept. Yet again, knowledge of the inner workings of professional wrestling perfectly explains current news events.
The purpose of a bad guy wrestler is to get the crowd against them so that the good guy gets cheers when he starts beating him up. The drama of any story cannot work unless you have a guy to root for and a guy to hope doesn't win. This is the same whether the story is a wrestling match, a game, a film, or a book. We all know the basic structure of any story - the good starts off weak and grows in power over the film until his world is turned upside down and he hits his lowest point where all looks lost to the bad guy and then he makes a dramatic comeback using the lessons he has learned during the film to overcome this obstacle and save the world/get the girl. That basic structure is so entwined into our psychology now that people even use it in their daily lives to justify their behaviours.
Anyway, the strength of any narrative comes down to how much we emotionally despise the bad guy. You can't have a strong good guy without an intensely disliked bad guy. If nobody cares about the bad guy then there's no threat so there's nothing to overcome for the good guy. Most people recognise this so then you get to the point of the matter - how do we make the bad guys really dislikeable?
There's a good way of doing it which actually good writers employ. This is by giving the bad guy a clear and consistent moral framework which you can see the logic in and all of his badness is a consequence of that system of beliefs. The Joker is a very good example of this in The Dark Knight. The hatred for the Joker from the audience came from his world view and all of the bad things that he did were a logical extension of that world view. He blew up a hospital but did so for reasons which made sense to him and outrages us. We call this good heat. Thanos was another example of somebody who had good heat or if you want to get a bit more complicated then Michael Corleone.
Another way of doing this, employed by hacks and terrible writers, is to just make the bad guy do lots of bad things or conversely make the good guy the saintliest figure in existence. They are bad because they do bad things. The go to example in movies is killing children, the elderly or animals. We have a visceral reaction to the act that they commit but not the motivations. There's no psychological underpinning to your dislike for the bad guy, you just like him because he did bad stuff. We call this cheap heat. When your bad guy has cheap heat then your good guy will never be as liked as they could be.
Back to Greta.
Greta is the perfect example of cheap heat. She's a young white European girl which makes her impossible to attack in any way without coming across as some sort of a monster. Her opinions don't matter, she has an automatic Get Out Of Jail Free card. She is good and virtuous because she is good and virtuous rather than having an internal consistency to her actions which can be debated or judged. If you try to judge her opinions as equally as you would do an adult then you're accused of bullying children.
This non-descript media friendly young girl has no good ideas. She is saying nothing revolutionary or different. In fact it would be fair to say that she's saying a lot of really stupid shit but she cannot be held to account for it in the same way as, say, Boris Johnson because of her inbuilt GOOJF card.
Her backers know this. They're not idiots. They've been using, promoting and funding children now for the last decade or so as a way of spreading their messages without discussion because disagreement is an act of victimisation, which is what I believe much of the modern left embodies philosophically.
She's no different from David Hogg or a million others. Another child with overly simplistic viewpoints being paraded around by the same old financial backers as a way of furthering their agenda without the intellectual honesty or discourse.