I don't ever remember being explicitly told that all jet guys were douchebags, but I definitely remember having that impression in primary until I met actual jet guys. So I'm not sure exactly how it was instilled, but it was there. As for the lifestyle thing, I definitely remember some VP types saying things along the lines of, "Ok...if you want to spend all your time on the boat not drinking or making per diem" in response to finding out you were interested in jets. And, in actuality, there is some truth to it.
I also distinctly remember getting the broad generalization of idea in primary that the helo community was "super chill," the patrol community had the "best lifestyle," and that in the jet community, "the lifestyle sucks but the flying and the mission are awesome." In actuality, none of those are remotely close to being true across the board - I feel like it's much safer to say that every community is relaxed about some things and anal about others, every community has good duty stations and crappy ones, and times of high opstempo and times of low, and every community has cool missions and boring missions. The low representaiton of the jet community in primary instructors does allow false impressions to build though - I know I heard many times that as a jet pilot all I would do was "burn holes in the sky at 20,000 ft." To generalize broadly, all broad generalizations are false.