solarpunk memes

but if you give people the opporturnity to do something that is convenient for them and fucks over others, far too many will do it.

That's called kleptomania, and it's actually pretty rare.

Normally, people are far too considerate of others and far too scared of even a slight possibility of losing someone's friendship or being marked as a thief to do things that fuck over others just because it is to their best judgment convenient for them.

Where it goes wrong is that people are placed in an artificial position where they are shielded from any such consequences. Where the best thieves hold the places of highest honor and wealth, where thieves have legal and physical protection if they steal the right way (including during scientific experiments, where the defectors are shielded from others through anonymity and the legal and social authority of the scientist), where people are forced to steal under contract under pain of homelessness. When there is no ethical consumption under capitalism, what more is defecting on the commons?

A mentally healthy person seeing the opportunity to screw someone over for personal gain warns that person that they've got a vulnerability so they can address it. They tell people when they drop their wallet. They look away from people typing their passwords. They give food to the hungry if they have enough to spare. They don't bother to lock their doors because to them locks are less binding than suggestions. Capitalism isn't the only force that get people to act like kleptomaniacs or xenophobes, but it is the first ideology that has managed to saturate the entire society with those modes of thought.