Because she demands people do things without doing anything herself or having any great knowledge or skill that would solve the stated problem.
It's holier than thou and sanctimony and undoubtedly hypocritical too. Like John Lennon saying everyone should live in peace or the pope saying, well just about everything he says.
It's like every family has a person who instead of helping them clean the house they stand and tell everyone else what chores need to do be done and ordering everyone around while the are trying to clean. "Put those books on the shelf....take the bins out..."
People that can actually do things vs people that are useless and just say that things should be done.
It's like most people realise the stupidity of someone saying "Why don't poor people just get better jobs", but they seem to fail and have a brain fart when someone says "Why can't we all just get along?" as though that's some kind of profound statement on world politics and "Hey, this school kid say we should just get along, if a school kid can see that why not world leaders!" but, you know, everyone over the age of 5 should be able to see why we just can't get along and why the school kid should be doing their homework and studying.
The world isn't changed by people sitting with cardboard signs. It's not made better by politics. Politics can (and often does) make things a lot worse. Technology makes things better. Progress. Smart people make the world better.
So her protesting about climate change is compounded by that naivety because she hasn't got the first clue.
And your idea "trying to make things better" is so facile and trite. She's not doing anything to make anything better. It's like people who don't shave in a month for awareness - they're doing nothing. Making a quilt for Ukraine. That's useless. But it's people who believe their useless doing nothing is better than everyone else's doing nothing. Watching the boxset of the Office for Rwanda. Why not that? Playing call of duty for breast cancer. I'm going to run around the park for cancer - well you run around the park every week you're just so narcissistic that you have make everything about you.
Lastly she suffers from that same disease that all useless political protestors do : she'll never be happy, she'll never accept the people she berates have done anything, nothing is ever enough. So even when we make significant changes - ones that actually make practical sense she won't say "Great!" she'll just continue to whine and the tragic thing is she criticises politicians for just talking with the 'blah blah blah' thing - which is like she realises how useless she is and is projecting her own faults on others.