Haters and gossip girls

I have a friend that is a gossip girl. Our only solid conversations are about somebody she wants to talk shit about. Let me tell you, some days I will wake up to ten texts from her with screen shots of people on Facebook she wants to gossip about. Don't get me wrong, sometimes I like to gossip about dumb shit I see on Facebook too but at the same time I am 28 years old and ain't got time for that all the damn time. Plus some of the shit she wants to talk about is mean as hell, like wanting to talk about someone gaining a lot of weight or someone who looks "ghetto", or someone who going thru some tough times. I am over it and have stopped responding to her constantly shit talking people. Sometimes she gets way deep into it and looks up people's employers and salaries and judges their income or she'll even look up people's family members and where they live and shit talk their house! Anyway, I thought this would be a good topic of conversation, about why some people LOVE to hate on others and constantly gossip. Honestly in my situation I think it stems from insecurity... I won't shit talk her here and be a hypocrite but girl has no room to talk when it comes to her hating LOL. Anyway, why do you think some people are such haters and gossip girls? Are they just insecure and hating on others makes them feel better about themselves? Are they jealous?