Anger and feelings of Guilt, Why?

Every time I talk about being an agnostic/atheist I feel guilty as if I am doing something wrong...that does not seem fair.  The way religion has incorporated itself into our lives is destructive in nature.  Most people in this country are so focused on christianity as the true belief they look down upon those who disagree.  What's hard is most of my family and friends feel that way also.

I was talking to a long time friend of mine the other night and decided to tell her a little about my beliefs.  I've been agnostic for several years, but had never told her.  As soon as I stated, "I don't know if I've told you or not, but I am agnostic", her voice changed to a defensive tone and she said,"what's that?" I tried explaining to her that I don't worship any gods and do not believe there is enough proof that they exist and there is more proof that they do not.  When I finished there was just silence with a hint of disapproval.  Needless to say I steered clear of that subject after that.

Also, when I post any agnostic/atheist statement on Facebook, it gets attacked by my mother and my best friends mother right away.  They don't even really read the post or understand what I am trying to say.  It's as if they look at it blindly just like they look at their religious beliefs and then comment a retort involving but my god is a loving god and blah blah blah.

I'm tired of the slanted view against atheists and people who don't acknowledge statements that go against their beliefs.  Whenever I say or post something, I read and listen to the responses with an open mind.  I am just asking for the same in return!