Why are some moderate religious afraid of atheism?

[Der/die AtheistIn]

Then please expand on that, because the moderates in the US are generally lukewarm toward atheism.

My whole family, not just my parents, are moderates and they would be schocked if I told them I'm atheist. There are some other people outside the family who think the same. I saw once in a german programm a family of muslims that was moderate, the daughters didn't wear any hijab or anything similar, except for religious ceremony. The eldest daughter was allowed to attend a judo class and she had christian friends. The family followed the tradition very exactly. The parents were very defensive of Islam, they claimed that terorrism isn't part of the real Islam and that they're sad when someone dislikes them for being muslims. Granted, they are associated with terrorism when criticized, but to me they also seem afraid of leaving their religion. They seem to be afraid of even trying to be atheists.