I get your distain for the stamp collector analogy lumpy it rather generalises both sides.
Richard Dawkins uses a 1-7 point scale to measure the strength of a person's faith and belief in god in his book 'The God Delusion' 1 is a person who is absolutely sure of the existence of god and lives their life in that vain on a daily basis. 7 is someone who is absolutely certain that there is no god.
'Atheist' isn't a dirty word, to some extent we are all atheists as we dont all believe in every god ever worshipped past or present.
But I just want to defend those of us who reject mono-theistic religion. Some atheists are vocal against organised religion because they have experienced great misery at the hands of it. Some people find as much comfort and clarity in the rejection of a belief in god as an acceptance of it.
The problem is, there is no 'book of atheism' that contains the ancient rules all atheists must stick to in order to be true atheists. If you are an atheist- you simply do not believe in a deity, or you occupy number 6 on Dawkins' scale, in that you live your life as though there is no god, but you cannot completely reject that there could be, as the existence of god cannot be proved.
Atheists can still be racist, they can still be pro life, pro death penalty, pro isreal/ palastine... There are no set rules.
In religion I'm afraid there are set rules, and if you call yourself a christian, be prepared to answer questions about unfavorable bible passages and christian values from non believers who feel they pose a challenge to a progressive society.
If you feel uncomfortable with the stigma- dont be a christian.
I dont put any people of faith in presupposed boxes, as faith (or lack of it) is personal.
For what its worth I've been the target of some disgusting comments from christians in my time, mainly evangelicals but other sects too. A good way to avoid animosity and rudness on both sides is to avoid compartmentalising.