You're redefining environmentalism with a very narrow and technical view. Goodhart's law does not only apply to computer science, but to ecology as well, and says that CO2 emission alone is not a good metrics.
I'm not saying energy consumption overall is a perfect metrics, but the degrowth movement is a philosophy / science that's not aligned on a specific metrics: https://en.wikipedia.org/wiki/Degrowth
I think to most people, environmentalism is mostly about climate change and pollution. You're free to widen the definition of course, but note that even that Wikipedia article basically calls it a fringe ideology (in different words).
Can you name specific issues caused directly by energy consumption as opposed to specific energy sources or downstream effects like pollution, which is avoidable?
The degrowth movement is very fringe indeed. But its ideas are not, some have even been assimilated by the green-washing apparatus such as "reduce, reuse, recycle". I agree with your definition because it includes pollution, which is deciding factor for reducing production overall.
> Can you name specific issues caused directly by energy consumption
The question is good but not the framing. How is pollution avoidable? Energy consumption is not the problem but it's the means by which the auxiliary problems arise, and therefore a correct proxy to measure them. One of the problems is production of throwaway goods of dubious quality (leading to enormous pollution), a problem which technically could not exist before we had an abundance of quasi-free energy.
It's like in software development when people consider CPU/RAM is unlimited and don't provide any optimization. That may be fine in hypothetical settings, but in the real world resources are finite. (the analogy stops because using too much CPU/RAM does not "pollute" the rest of the machine and create memory corruption or whatever)
> One of the problems is production of throwaway goods of dubious quality (leading to enormous pollution), a problem which technically could not exist before we had an abundance of quasi-free energy.
Yes, but my entire point is not only is this solvable without throwing the energy baby out with the dubious quality goods bathwater, it's easier to solve with more and cheaper energy.
If the consumption of abundant energy has negative externalities, then those need to be appropriately priced. At that point, buying pollution causing junk will become more expensive than buying clean junk, but we'll still be able to afford the clean junk we want.
I'm not saying energy consumption overall is a perfect metrics, but the degrowth movement is a philosophy / science that's not aligned on a specific metrics: https://en.wikipedia.org/wiki/Degrowth