It's difficult to determine blame between the tool and the users. After all reducing something into a general idea is what humans do a lot of the time anyhow, but like astrology using it as anything but the surface approach little bit of entertainment that it is, causes dangerously preemptive idea's about other people.
There really is little more to it than seeking a pattern and hoping it fits. Obviously I'm biased against it as I despise and fear the idea that a person would deal with me or engage with me on the notion of the type they think I am, rather than as another human being.
Now I know that seems a bit unfair but I think its almost impossible to avoid a theory like this influencing how a person looks at others.
Also I have met very few people who claim it has somehow helped them in a real way. In many cases I see a person talking about a relationship it has helped with, but all I see is someone who decided to take a different approach and become perhaps more empathetic towards others and considerate that people see the world differently. But to me it would seem a person could come to that conclusion on their own without the need of an apparently pseudo-psychological theory that merely tricks them into doing so.