For many people in non first world countries this sort of existence is standard - not something to be blogged about with artfully composed photos carefully edited and posted to the internet.
So I guess the comment was provoked by something like that. It was certainly one of my reactions reading the piece. I also thought “oh that’s cool, I wonder how they did it” but it was very short on detail, made up for by self-congratulatory back patting.
Maybe the person making the comment lives in a developing country and finds it a little jarring to see “solarpunk” cosplay.
I think you and the other person are reading far too deep into one person's contentment with a humble living space. It's clear they are safe and comfortable; that doesn't translate in any way to suggesting other places where this living style (sans electricity or safety) should just pick themselves up by their bootstraps.
It's a particularly offensive part of white culture that fetishizes a "return to the land" while billions around the world are trapped miserably eeking out that existence with literally zero opportunity to ever have anything else.
The only reason you feel "happy" for them is because you know its a cosplay charade they could walk away from at any time. Otherwise we would call this what it is; destitute poverty.
But - cosplay - 100%
They're trying to have a developed world quality of life in a low-resource/low-cost way. In some ways, beyond average developed world quality of life: the place they're living is stinkin' gorgeous.
I don't know if it's generally practical for most people or even as energy efficient as living in a modest apartment in a large city (the transportation issues around food, medicine, and necessities factor in), but it's not an uninteresting thing to explore.