Trickquestion
It’s not that ponies can’t be jerks, it’s the main characters that shouldn’t be jerks, at least not in a way that’s being treated for comedy. They are supposed to be the embodiments of friendship, so when they’re suddenly callous assholes for the sake of a joke, it’s both unfunny and completely at odds with the entire premise of the show. It’s why Rainbow was such an awful character up until season 3 showed us she’s capable of not being an asshole for an extended period of time.