Why do people hate others who lose weight?

I'm trying so lose weight and two of my friends called me a traitor and the told me, "Big girls should stay together! Now you're trying to lose weight. Traitor! Don't lose weight. You don't wanna be a skinny slit." I was shocked when they say that. They won't talk to me now because I "betrayed" them. Wtf is wrong with people?! I am now 224lbs. I was 230lbs. I'm a large girl and 6'1. I got call a "Big Fat Pig" and "You need to lose weight" "Fatty". Man we can't ever win!