DIRECT CAUSE of human pain and suffering in the form of rape, holocausts, genocides, natural disasters, murder, child molestation, and his only reason to do so is... What?
That's a rather harsh way of putting it, and shows just why people take it so offensively, because they don't realize the complexity of the issue but think of exactly what you just stated in that sentence.
One ultimate point you need to understand is that during the Middle Era, when theology wasn't anywhere close to as available to commoners as it is now, religion was just a part of daily life that it might as well have been cultural. It's weird to think of a theology as a culture among people now, but back then people didn't get too deep into the background of specific religious ideas, they just thought "oh we better get look nice for church," or "tomorrow I have to light the candle at the local shrine."
This doesn't just apply to Christianity, it applies to various religions ranging from Shintoism to even Native American beliefs. All of it was so deeply ingrained from the community that it became a mindless (in a respectful sense) cultural phenomena that everyone followed.
Which brings me to my main point, religious communities and America. We live in a society where different cultures mix in a hub designed to attract markets and people alike. This results in Muslims and Buddhists to live alongside American Southerners (known for their staunch religious affiliation whatever it may be).
If someone were to tell another person that "it was all just a part of God's plan," then why should the other person be offended? We live in a larger culture that accepts other ideas openly and without offense, so why be offended when you have no clue what another person means by their statement? It's like someone that always speaks in confusing zen phrases (for some odd reason) and getting offended by them because you thought they just called you a cricket, wtf? I'm not a cricket!
My point is that our society that accepts other cultures and ideas shouldn't let them be or attack them, but make it a part of our everyday lives. So if you think it's ridiculous that you have to provide a second Microwave for your kitchen because Muslims will not eat from a microwave with the presence of pork in them, why attack their ideas and just live alongside them peacefully? Get the damn microwave.