It is curious, but although "sick jokes" in general can be very funny, a rummage on Sickipedia finds much crudity but little wit arising from Jage Goody's cancer. That may be contrasted with the death of Diana Windsor.

My initial supposition is that the engine room for funny gallows humour is a affection for the subject matter.

I do not, however, understand why Gargoyle says that jokes about death are not a "coping mechanism".