You apparently didn't read the site very well. It does in fact attack Christian denominations, so it's not like they are out to get every non-christian belief system. They attack anything that doesn't follow the exact same lines of belief they do.
Why you are getting so upset by it all is beyond me. Just as you are free to come to this site and discuss how upset you are by other peoples opinions, others are allowed to create websites and discuss their anger about opinions.
If it doesn't directly affect you..don't take it personally.