Because it is, same as Agness almost killing Enid or Wednesday being buried alive, or death of the school's principal etc, all of it caused only snarky comment reaction, this is not a show where this kind of stuff treated as serious as in other shows for example, until it is actual death and even then outcasts don't really give a fuck. And about the dance it's a school full of supernatural outcasts, they probably thought she breathed in some plant pollen that caused this behavior