I'm an atheist, but I still sometimes go to a UU church. I never pray, but I will sing a little pagan chant now and then if the message is positive and empowering and helps me shift my frame of mind---but I don't believe anything magical happens. It's more like an affirmation. So I may appear to be acting like a theist--sometimes. More important than my actions is my motivation.
One could say that an atheist has relative morality, but I think this is true for everyone. Someone that believes certain things are wrong--regardless of circumstances---can definitely convince themselves of an exception when presented with a situation where they SHOULD weigh all factors before making a decision instead of falling back on some black and white understanding.
So that may appear they are acting like an atheist.
One thing that I have learned from leaving a cult, people usually can't be defined all nice an neat. Most things I thought about them were just wrong. Humans operate in so many layers, that anything beyond loose generalities is just worthless.
NC