Self restaint vs systemic restraint
It’s not hypocritical to help yourself at a buffet at the same time you counsel the owner of the restaurant to limit the number of trips that people take so that the restaurant can become sustainable.
It’s possible to argue for systemic changes to cultural systems while also doing what classical economics posits that people do–which is focus on self-interest.
In fact, it’s this very conflict that requires us to argue for systemic change.