Fattism: discrimination on the basis of weight, esp prejudice against those considered to be overweight

I had some pretty horrible things happen to me in the last week.  Here is a synopsis:
1. a girl, we'll call her Jamie, said "I would rather die then to be fat. Vain sure but it's not worth the pain and suffering that comes with obesity."
2.  I said, " I'm sad for you that you'd rather die than be fat. If I thought that way I would have died in high school. I have suffered from obesity most of my life. The only way it hinders my life is in dating. I can do everything else. Even workout. Which I do. I got 2nd degree burns on my foot in high school & the sudden stop in activity caused weight gain. I've had a difficult time since then. It'd be selfish of me to choose death over facing this trial, dealing with it, & continuing to fight it. I know I am beautiful just the way I am. But I am always working for more."
3. Jamie said, " I sure hope one day you experience the liberating feeling it is to she'd the fat person trapping you in life!"
4. Then she said, "You have an amazing intellect but you are so blinded by the culture [your] church. You have a beautiful face but sorry few men will look past that if you indeed are seeking to marry."

So basically, I need to "shed my fat" suit in order to find a husband?  I don't understand how a person like this can be so cruel to a person, especially a person on an online forum that they've never met.  A person who is a member of the same church, a Christian church.  Where in the words she said was she behaving in a Christlike manner?  When did it become ok to be an online bully?  The things she said were very cruel.  More was said, that I left out, but those were the important parts.  

The questions this makes me ask are 1) why are people like that? 2) what can I do so that when people do say those things they won't effect me in a negative manner?  3) what can I do for that person so that they won't unleash their bitterness on others like they did on me?

That night I was pretty upset.  So upset I went an got pizza for dinner.  That's not what I need to help me get healthy, but sadly that's what happens.  In the days since these things were said, I have done pretty well keeping motivated.  Today I walked 2 miles around my town and also did a 30 video with weights.  I'm so ready to get this week off on a positive note and leave behind all the fattists.