I think humanoid is a perfectly logical end-state for any terrestrial species that develops technology:
Gotta get energy somehow, consumption is more energy dense than autotrophy, so need a mouth. Gotta find the stuff to put in mouth, so need sense organs, closer to mouth is better. Light is generally the best medium for sensing, so eyes eventually. Two eyes are way better than one for depth perception, but three is inefficient energy investment with seriously diminishing returns.
Gotta move around in a gravity well to get to your food, so you need some kind of limbs. In the beginning, before developing the sophisticated nervous system necessary for dynamic locomotion, four is the minimum so you can remain stable on three limbs while you move the fourth.
Gotta start banging rocks together if you want tech, so you need hands of some kind, and two free limbs. By this point, your nervous system should be sophisticated enough to allow dynamic locomotion, but you still need at least two “legs” to move relative to each other to move on the ground in a gravity well.
I would expect most technological species with similar heritage to humans to look roughly humanoid. There are plenty of other forms, but I feel like they’d be selected against.
As I’ve said, if you convince everyone who considers their environmental impact to not have children, who does that leave having children? What becomes of the environment when it’s only the environmentally negligent raising future generations?
All I’m saying is that there’s a logical breakdown at play. Any argument in favor of “the environment” had to be based on the value of individual life. I’m not even saying that we shouldn’t be moderating our population growth, we should. I’m just saying the environmentally friendly angle is a logically strange argument, from first principles.
Sure. But your framing of not having children as “environmentally friendly”, if embraced, results in only the unconscientious people having kids. That’s literally the premise of Idiocracy.