The author lost me at the end when they said to stop pulling up dandelions. Dandelions are not a native species (at least in North America) and are not a good food source for native pollinators.
For overcoming pitchiness, the "one weird trick" I learned from a singing teacher is to imagine you are moving in the opposite direction from the actual pitch. If you're going higher, imagine you're going lower and vice versa.
This helped me overcome the tendency to constrict the throat when reaching for a higher note or to go flat when heading lower.
"There is genuine suffering in the world that it is important to do something about"
You're right. But as the Buddhists say "Start where you are." How are you going to address all the suffering in the world if you can't address the suffering in your own heart or your own home? I would even say that, for some people at least, their frantic efforts to fix the world outside are simply a way of avoiding dealing with the world inside.
And it is certainly true that efforts to bring peace are probably more effective when they come from people who are living in peace with themselves.