that being said if I saw 20 youths from obama's church surrounding my parent's house I would take action.
If 20 Mormon youth surrounded the house I would be concerned that they may cut the grass too short or paint the trim the wrong color.
Let there be no misinterpretation of where I stand. Mormonism is heresy and is not Christianity. It's a cult in the same sense of Scientology, of which Greta van Susteren is a notable member. Jim Robinson has made things crystal clear concerning Mormonism, stating:
The so-called book of Mormon is false gospel, ie, fiction. It has nothing whatsoever to do with Christianity or the Word of God.
On the other hand, although I don't know any Mormons personally, I tend to think, on temporal matters, they don't present much of a danger. Your latter (pun intended) point is probably quite right about Mormon youth.