It's both. Newfie jokes usually play off more of a bumpkin sort of dumb than just outright stupid. Though I gotta say, hearing a Newfie joke sounds like a bizarre relic of a long-gone time, like if you heard another American making Jens Jensen jokes about Swedish immigrants or something.
Like, I heard them when I was a kid, and they'd been around forever, but I never hear them anymore and haven't for years. They've died down to pretty much just "that old guy at the office ALL of whose jokes are horrifically dated, no matter whether they're offensive or not".
Though maybe that's not true in Alberta or the other prairie provinces, where you still see a lot of Newfies going for work.
That some of those are considered only Canadian baffles me, like kerfuffle, gong show, or deke. Really? Those are ours?