Fundamentally, I'd argue that very little should ever be unreasonable or out of bounds to make jokes about; what is important is that it's good humour.
Case in point: https://theonion.com/hijackers-surprised-to-find-selves-in-h...
And, as you say, in Chuck Norris' case, it's virtually obligatory.
> Fundamentally, I'd argue that very little should ever be unreasonable or out of bounds to make jokes about; what is important is that it's good humour.
On a personal level, I couldn't agree more. I do hope that culturally we get to that point at some time :-)