Yeah, using fire as an example was a tactical mistake. But I liked the point you made, using shelters: you won't compromise your low-impact principles to reduce pack weight when it results in obvious and direct damage to the environment you're passing through. I think that's pretty much how I feel, too.

We can mire down in specifics all year: you used shelter. We could also discuss burying garbage versus packing it out, ditching around tents, burying toilet paper versus packing it out, tents (crushing vegetation) versus hammocks (girdling trees), and merely the impact of one's foot on fragile environments (I've read two-page discussions of whether it's better to walk single file or spread out in a line in a meadow, or plow through the mud rut rather than widening the trail by going around.)

For me, I think the line comes at obvious damage: I'll carry what I need to avoid the obvious damage, and try not to think about the hidden damage (the damage to the environment caused by the far-away drilling and manufacturing needed to create all those neat pieces of gear that let me avoid the obvious damage to the backcountry area I can see around me.)