The everyday media consumer can see it a bit on American pundit shows, especially ones like Morning Joe Scarborough and variously on things like the Cspan callin shows.

I.e. you got to seek it out and willfully steep youself in poltical punditry.

That said, if you ever find yourself working on the political campaign of a progressive challenger to a conservative Democrat, you’ll get it directly. But I have never seen the defeatism assocated with anything leftist, always more as the criticism of Democratic party conservatism.