Not irresponsible, more like selfish/emotional?
The thing is Eclipsa's selfishness is appealing because we would do the same in her place.>Assholes imprison you and destroy your family>You have the chance to get everything back, just need to convince one of the assholes to free your husband/wife>Asshole won't listen and keeps insulting your beloved so you get mad.>Fight happens yada yada... fuck it, if the asshole's not doing it I'll use everything in my power to do it.>In Eclipsa's case she switches bodies.
Up to this point the episode is great and so is the character as we can understand her frustration, yet we know SHE IS DOING A BAD THING to achieve her goal.
The problem isn't Eclipsa, but Star. The episode would be a 10/10 if she had understood she is being using msgic selfishly too since the begining of the show by watching another person doing it (damm, 3 episodes ago she transformed a peasant into a disgusting creature for no reason)
But no, Star acts all superior, critizices Eclipsa, makes her stop and learns nothing.
So what the show is implying is that Star is the only one allowed to be selfish and cruel to achieve her goals. The rest are labeled as evil.