I think that conservative means "in support of a (certain kind of) status quo" in this case, rather than the American line-up of hot-button culture war issues. The upper middle-class wants stability, whatever it is, because of the structure of their income stream. That's why upper middle class people are basically centrists and don't want to rock the boat too much: they're doing very well in the boat, and rocking it will have them taking on water. Other folks have much less to lose (which we should all remember over the next month).