I thought it was pretty explicit that the MC has selfish motivations (He wanted to be an astronaut when he grows up and he's going to get what he wants), and the designated antagonist's flaws are literally everything about Anarcho-Primitivism which we make fun of. I consider the actual main characters to be the villagers, who are repeatedly shown to not be as stupid or helpless as one might expect from this kind of story. They straight up re-invent the water wheel with no prompting from the MC just by observing the mechanisms he already built and noticing that the same principles apply to a flowing stream.