

Put your cart back when you’re done shopping
OP didn’t make a blanket statement that “anyone who does X is a piece of shit.”
He said an unwritten rule, like your own statement:
Don’t be stupid
Which is significantly closer to ableism than the shopping carts, with the implication that anyone who is stupid is a piece of shit.
I don’t think there’s anything wrong with saying “don’t be stupid,” for the record, but in case you weren’t aware, people with brain damage are included under “anyone.”
You’ve picked a bizarrely specific hill to die on.
Try not to stress too much about it while you’re away! If nothing can be done, nothing can be done. Solarpunks need to be resilient to things like this anyway. Community over convenience.