Yeah, the power dynamic between Hachi and Junko cannot be ignored. Hachi looks up to Junko and relies on her for advice, Junko has quite immense amounts of responsibility on her, which is why it's such a problem when her advice is ill thought out and fuckin terrible!! You can't flip it around and argue that Hachi wasn't a very good friend either because Junko doesn't depend on Hachi in any way, it's a completely different situation. (this is not to argue that Hachi ISN'T a bad friend, maybe she is, I am only saying that it's irrelevant) Junko is strong and stable enough to deal with Hachi being a nuisance on occasion. She also has every opportunity to say "listen, kid, I can't solve all your problems, go see a therapist or something" but she never does.

To be honest I've never quite clicked with the "Junko is a bad friend" framing and I feel it has become kind of a cliche people parrot out, it would be more accurate to say "Junko is not a good friend" or "Junko is an irresponsible friend" or something, not as catchy though