Atheists who announce "I'm good without god"

[Whateverist]

Yes and no.  People can and do vary regarding which central values dominate the manner in which they believe they should behave.  So when faced with a situation in which one choice would best serve the value you place on loyalty but a different choice would better serve the value you place on fairness, yes we can certainly disagree.  There are regions of near unanimous agreement but there is also inherent competition between values.  It is important to avoid oversimplification when studying morality.

Agree,but it does start off simple and then one gets to the not so simple. Take, for example, "Thou shalt not kill." Seems simple enough, but then the exceptions start getting lobbed in like the Holy Hand Grenade of Antioch.
Home invasion? Shoot the perp. That's moral.
War? Shoot the enemy. That's moral.
Different nation? Genocide them. That's moral.
And so on. 

Theists always end up trying and failing to defend their immoral god.

Admittedly there is much more hay than than silver needles in any pile of Christians but there really are a few needles in there too.  I've found a few and frankly I'm not interested in talking with the straw any more.  But why waste your time slinging insults with them when they do not represent the best that religion can do?  Of course they're stupid and stubborn and predictable .. so why go there?

Also, apart from evangelizing for atheism, what do you hope to accomplish in any conversation with someone who holds religious beliefs?  Always a good idea to reflect on your own goals so that you have a better chance of achieving them.