These people are singlehandedly saving _millions_ of laptops from going to the landfill one day. That's a valiant effort and they're doing it wonderfully. Regardless, one of the points of Linux is to install it on as much hardware as possible. Do you think people that managed to get it installed on iPods, PS5s, Wiis, Chromebooks, routers, Nintendo Switches, etc. should all stop just because they're doing something unsupported? Most of those cases were met with friction by the original OEM. If anything, Apple has been pretty laissez faire about the whole thing compared to Nintendo and Sony who will ban your console if you hack it.
Those laptops don't need to go to any landfill. They are much too precious to not recycle the metals and other materials and will be taken care of if you return them to the manufacturer. (by law, at least in the EU)
Still, reuse > recycling
Recycling the metals is obviously far less useful than being able to still operate them even if Apple stops macOS updates for them!