Those jackets are 100% a flex, but they (and their competition like Arc'teryx, Moose Knuckles, etc.) aren't a flex in the typical middle-class way of overpaying for a middling product because it has a trendy design. They're a flex because you're telling the world that you're willing to drop $800-1200 on a coat so you can wear whatever you want underneath and don't have mess up your outfit with layers.