They care, but see "capitalism" as the root problem and revolution as the only solution. It is just, that their concepts of what comes next, are quite vague.
Oh, many have at-hand solutions alright! It's just that these heart-warming intuitive solutions break down when faced with realities of scale.
> Wind turbines deface! Solar panels pollute to produce! Batteries are full of metals you have to dig for! Screw industrial-scale food/production/distribution! Proof: I buy from the local shop/market/producer!
Yay, getting your Thanksgiving turkey from the local farm sure is nice, except... how much local producers have to produce to provide continuous daily sustenance to, say, a ~1M town? How much surface is needed to produce that amount? How are the logistics handled to move such local goods around? How much energy is expended in the whole process?
I'm not saying the ideas don't have merit, it's just that the revolution as envisioned falls apart with a bit of system thinking and a couple minutes of napkin math. That, or decimate the global human population and have survivors live in extreme scarcity.