Good question..I have been wondering about these things myself too, in fact I said pretty much the same thing to myself, which is why it took me a long time to take the step to even ask for testing to be done.

Maybe some people actually think a label simply is some kind of 'bad' excuse. Especially if you wouldn't really see anything about a person that strikes as being odd, or they be like, oh well everyone has some 'weird' traits, or like isn't everyone a little autistic, or they have this image of extremely low functioning people and your 'case' wouldn't be bad enough... Also if you are functioning well, despite thinking or knowing you might be autistic/have autism (whichever one prefers) a label can be stigmatizing in some way.

Personally I think if you really need help in understanding yourself and learning to deal with it, a label is like a tool to reach that, or at least understand why things don't work out despite trying very hard. About abusing labels, I have this very strong sense of needing to do everything everyone else does, that's despite having both autism and a metabolic disease label, so I try even harder instead, which often leads me to becoming severely overwhelmed. I like to one day be able to just accept I need to let go of pushing myself too much and don't feel so ashamed when things don't work out.