I've almost never been autofilled to support, but I've been autofilled to jungle several times. I think it's an unpopular role because junglers are much more prone to being flamed than supports now.
If you fail a gank, you get flamed. If you take someone's kill, you get flamed. If you happened to be farming nearby when one of your teammates dies, you get flamed. And, of course, if your teammates lose any of their lanes, then it's obviously not their fault; it's your fault for not ganking enough.
I'd enjoy playing jungler a lot more if my teammates stopped using me as a scapegoat.