I think we all acknowledge that types may "go bad" in certain ways (even Jung briefly touched on it), but exactly how is not something there is a lot of info on because when a person becomes unstable their personality can get so distorted it's difficult to type them accurately. For example, it's been discussed on a few INFP forums how depressed people tend to test INFP even if they are not, simply because of how the test questions can be interpreted. This distorts the image of what an INFP looks like; how do you tell the unhealthy INFPs from the unhealthy mistyped INFPs? There's no road map for that. As mentioned, enneagram has levels of health, which is useful in determining a person's type, no matter how stable they are. Unfortunately, MBTI does not have that, yet.
I get the sense the OP is more annoyed at what is being labeled "unhealthy". Well, I don't really see "unhealthy" being used to degrade a type's normal traits just because they are not a social ideal.