If you belong to the people who have a problem with using the terms "good" and "bad", here's an approach that might help you.
Replace good with the term "functional", and bad with the term "dysfunctional".
You still have to be careful, because although these terms sound more objective or scientific, as they are used in psychology for instance, they still can be used as a weapon (just like the terms good and bad can be used as a weapon). In general, a person doesn't want to be seen as dysfunctional in the same way a person doesn't want to be seen as bad.
But using these terms helps to understand what good and bad actually means when looking at things in an objective way.
For example, let's call the so-called good ETs "functional ETs", and the so-called bad ETs "dysfunctional ETs". In doing so, one important question becomes visible: Functional or dysfunctional in regard to what?
The simple answer: In regard to personal relationships.
A functional ET would be a being that is able to create and maintain functional relationships, whereas a functional relationship is a relationship that benefits both sides and doesn't lead to harm for anybody.
A dysfunctional ET would be a being that is unable to create and maintain functional relationships, meaning it is unable to have relationships that benefit both sides, or their relationships will lead to harm to the other side or a third party.
In short, dysfunctional means that whatever it is, it doesn't really work for all parties involved. At least one party is thrown under the bus for one reason or another. Put simply, at least one party involved would say: "This is bad for us."
In the same way, you could speak of functional and dysfunctional humans, or functional and dysfunctional AI.
It applies to all ISBEs in the exact same way, and that's why it's objective.