That too, but at the concert, they did it, because they performed before them. At least, that's what people said.
I'm pretty sure those idiots even chanting: "Wonder Girls!" or something like that.
I don't think that's the reason. The order for most Kpop concerts is senior idols or more popular idols sing last or close to last. SNSD going earlier would make sense because they're rookies. TVXQ would have been near the end or right at the end.
Yeah they did chant wonder girls to spite SNSD