I would even go so far as to say this is the general pattern of individuals learning models with explanatory power for dealing with reality. First, you learn the model, you try to apply it absolutely everywhere even in places where it won't work, you learn its limits, you then synthesize it into your holistic understanding along with every model you've learned thus far.

I'd say it's a reflection of an earlier stage of interpersonal maturity to try and put people into categories. More socially attuned people realize the complexity of other people and situations and synthesize all the available information to make a decision that is truly reflective of reality.

It's interesting to think how this affects self-perception. Basically this applies to how one views and treats themselves. One approach is to read book, take a test and put yourself in a bin: "well, I'll never be able to do xyz, the book said I am an abc". There is a danger there self-limiting and making the same mistake putting others in bins.

You must have read Changing on the job :p