christians, of ALL people, should not judge others

i teach my children to treat others as they want to be treated.  i show them how to be charitable and kind to others.  i teach them that being mean isn't nice; that being different, is OK.  i teach them that saying naughty things is unacceptable.  and when they play "guns", i tell them what real guns do and that, while it may be just pretend while they are playing, real guns are not something to play with and they can be fatal.

i could go on and on telling you why i think i am a good person, especially in my heart.  my actions, feelings and what is in my heart has never really changed.  when i was a "christian", i still did all those things.  now that i am a "non-believer" or an "atheist" (i don't really like labels; i think they belong on your ketchup bottle, not on me), i continue to do all those same things.

both theists and non-theists can quote examples of the opposition of oppressing, killing, abusing human beings all in the name of what they believe.  it is published that stalin was atheist AND it is published that hitler was a christian maybe even a catholic (at least, in childhood; according to sources i've read about, he never "officially" disconnected from the catholic church; although when he left his parents home, he was never known to go to mass or have connections with with the catholic faith.  

but it is not for me to say if another is a christian, a catholic, a muslim, a non-believer, etc.  if you tell me you are a christian, then you are a self-described christian.  if hitler stood before me and proclaimed his allegiance to god, i might doubt it based on his actions but at the same time that if is how he described himself....  and according to the christian's good book, if he had prayed and repented (and had not committed suicide), god would have welcomed him into heaven.  

it's a circular argument.  but it seems to me that a christian, of ALL people, knows that they can not fairly (and, again, according to their good book, shouldn't) judge another's morality.