Joseph Smith was called a prophet, dumb dumb dumb dumb dumb

When I was in high school, I had a class with one of the most ego-maniacal assholes (excuse the language, but it's the only way I can express my distaste for this person) anyone would ever meet. Even though no one who reads this would know this guy, I'm not going to post his name, but I couldn't stand this guy. He would constantly attack my faith, completely unprovoked on top of that. One day, he was really being a jerk, and a guy sitting at our table kind of chimed in. Can't remember what he was attacking, but I remember it had something to do with Jesus. The other Christian chimed in, and I really didn't even care what he was saying, just that I had someone else on my side. It's nice to have someone else on your side when you're constantly being attacked and put down for your beliefs, especially when they're pretty private beliefs.
Well, apparently the guy was a Mormon. I didn't care at the time, because honestly I didn't know that much about different beliefs, etc. I've been thinking about how I'd feel if he chimed in while I was fighting with a-hole now. Honestly I think a pretty natural reaction would be something along the lines of "look, I don't need YOUR help." I'd probably treat him like "I'll tell you why you're wrong later."
I like to think I'm pretty accepting. I don't think Mormons are Christians, nor do I believe homosexuality is right, or that sex before marriage is okay, or anything else that's pretty controversial. And while I don't attack these people the way most Christians do (meaning I don't attack them at all, not that I attack them in a different way) I think there's a stigma around the fact that they are all sins.
The Bible has this running theme that people are to have a faith like a child. Basically, that means we're supposed to live life completely trusting God, not allowing logic, or our problems, or whatever else that might cloud our judgment or trust. I can't help but wonder: does the fact that we are aware of these sins automatically make our unloving hearts unable to love these people? Is there automatically a stigma about a person when he or she tells me: "I'm of the Mormon faith"? While I want to share this love that I've found in Jesus, am I automatically at a disadvantage, simply because I don't know what it looks like to love people?
This isn't one of those things I really beat myself up about, because I think to be able to love people unconditionally is pretty much impossible. Jesus proved that it is possible, but no one else has ever lived a life like Him. I'm sure Mother Theresa even wanted to take a shot at someone in her life.
On top of all that, is there anyway I could bring myself to love someone like a-hole? That's something I probably can beat myself up over... ;-)
Just a thought.