Not everything needs a label. Everything is not black and white. There is always a grey area. We as people get so caught up on the diagnosis that we ignore all the symptoms. Wouldn't it be nice if everyone just got along and stopped worrying so much about these labels?
While placing labels on things can be extremely damaging, it is an innate part of our basic human nature. Psychologically, humans use labels as a way to classify information as it comes to us and be able to effectively process this information. Using labels make processing this information easier because we can draw relations between different things more quickly than taking every bit of information we digest as unique and different, therefore expediting the cognitive process.
People feel the need to put a label on everything because it gives them the excuse for not doing their own work. The funniest part is people don't read labels. It just makes them feel good. Behind every label is the real reason - a lawyer. Follow the money for the answer.
If the recent election has taught us anything, it's that people see the world in black and white. They think that they are right and that everyone else is wrong. They can't see how anyone else could see it differently. It helps people feel better about themselves to put a label on something.