So if it was an ad featuring, say, a Finnish-accented character playing up the well-known Finnish reserve, would that be offensive? What if the Jamaican had been black? What do white Jamaicans sound like? The guy in the ad?
I'm mortally offended by almost all commercials aimed toward women--portraying them as dimwits obsessed with bodice-ripper romances and their delicate digestive tracts. Much worse than this light-hearted bit, I'd say. (Which has obviously had its intended effect, as we're talking about it.)