> Energy usage doesn't have to correspond to environmental damage much at all.
That says that you don't understand the problems. We (Humanity) have 3 problems:
1. Mass extinction. It is a fact, we are living it, it's measurable and it's very bad. It is not at all due to climate change.
2. Fossil energy. It's harder to see in the US, but in Europe started feeling it in 2007. Fossil fuels are limited, and at the moment we've reached the global production peak in 2018 (2019?). Fossil fuels are of course a cause for global warming, but the end of easy access to fossil fuels is a problem in itself. A "degrowth mindset" is not necessarily an ideology, it's a rational behaviour towards a future with less fossil fuels and therefore less energy.
3. Global warming. Europe can feel that it gets worse every year now. It is just starting, and it's never going back. It will keep getting worse, and nobody alive today will see it get better. The only thing we can do to limit how worse it gets is by using less fossil energy, which brings us back to some kind of degrowth again.
Don't mistake everyone who plans for degrowth for people who desire degrowth.
The whole problem with the US is the growth mindset. Because the US will military invade other countries long before accepting that degrowth is unavoidable. Any country who believes that the US are an ally is making a mistake, and the US have made it exceedingly clear in the last few months: the US don't have allies, just (temporary) partners and no notion of loyalty.