Why atheists offend the faithful

This is only speculation on my part, but.. I can understand why someone would be offended when I say "I'm atheist".
When I say that to someone, especially when they're extremely devoted, they will take offense to it, or at the very least be somewhat taken back.
Essentually, when I say that I'm atheist, I'm saying:

"Everything you hold sacred and center your life around, I've rejected as truth."

Now, if you take this sentence and apply it to anything you've ever held dear or sacred, you too would be offended.

However, there is a major mistake being made from the offended. They assume that the atheists have dismissed their belief off-hand without investigation or without thought. This is, for the vast majority of the time, not the case at all.

But when someone replies with "I'm muslim" or "I'm hindu" or "I'm mormon" or "I'm Christian", it infers some level of acceptance of the divine. So, it's more along the lines of:

"I accept a form of your sacred truth, just not yours in particular"

Which is a bit easier to swallow. It could be thought of as misguided or incomplete.

I don't care what people think. I've investigated all my life and continue to investigate the question of the existance of god and the divine. I have found NO evidence that would lead me to think there is an inkling of a divine.
That does not mean there isn't one. However, I can as safely say that there is no god as safely as I can say there is no superman living among us.