A little experiment for you:
Think about your hobbies. What do you like? Walking the dog? Maybe playing some Backgammon? Chatting online? Did you find something? Your favourite hobby? Can you find a noun that discribes you as a person with this hobby? Like Tennis Player or Environmentalist...
Now think about your favourit animal please. Got it? Same thing as before, is there a noun? Are you a "Cat Person" or a "Dog lover" or something else?
Your lifestyle. Are you an "Early bird", a "Vegiterian", a "Sleepy head", a "Smoker", a "Couch Potato", even more than one?
How many nouns like that did you find for yourself? 5, 10, more?
Maybe by now you get where I am going with this. If not:
People tend to put labels on everything. It is in our nature, it helps us understanding the world better. And there is in general nothing wrong with it.
We are social and like to be in groups that share same interest, and how build groups like that if we do not label ourselves.
But there is a label that some people in that group just refuse to use. It has such a bad "spirit".
"Atheist" a person that does not believe in a God or in Gods. This is all. But the word has this weird power to make a person with that label seem bad.
Why is that so?
Well If the majority of people around you use it in a negative way it gets stuck in your mind like that period. If you grow up in a very religious place and people keep talking about atheists in a very negative way then this is what you associate with it and if you finally discover that somehow you do not believe and should call yourself that you get a weird feeling of "i don't want to be called that".
Not only from that perspective
The other point is, if I am labelling myself with things I don't like or believe in I will get a ridicolously long list of things. We already have our long list from the beginning with things we do like. Now do we need that for the opposite too? I am a "no beer drinker" and a "a-unicornist" and a "no TV owner" and a "no ego shooter player" and a "a-flying spagettimonsterist" and a lot more. Get the point.
What did I want to say here?
>> If you do not like to label yourself but don't try to stop others labelling you because you can't.
>> If you are an atheist and you do not like the word, don't use it but don't expect others to stop using it.