I don't know specifically about the people you are talking about, but usually people are concerned about their status in their social group, and it makes them feel better to put others down. It makes them feel like they have higher status. They usually need to feel this way because actually they feel like they have low status and they don't like that, so they try to make it seem like others are even lower and therefore they are higher. They may be having a lot of troubles now or they had them in the past, and rather than try to work out their issues, its easier just to put others down so they feel higher than them.

I deal with people like this by ignoring their negative talk and encouraging them if they say something positive. And I try to find out what their real deep issue is, that is making them feel bad about themselves which I think causes them to be negative toward others.

But if things never get better, all you can do is try to stay away from people like this.

I hope things work out for you, in this situation! It's good sometimes just to talk about your own feelings, like you did here. I hope that helped a little. :)