I love this one!
I would point out that, as far as know, there are no analogous jokes in English about Bugs Bunny and Daffy Duck, or about Tom and Jerry.
Possibly such jokes would be completely superfluous, because the original cartoons (especially from the "Golden Age" of the 1930s/1940s) were already full of sadistic violence, as well as sarcasm and sexual humor. See, for example, Tex Avery's famous parody of Красная Шапочка, from 1943:
So, possibly, the Винни-Пух cartoons became a natural inspiration for "underground" dark humor because the Soviet system of film censorship made it impossible for an animator like Tex Avery to flourish publicly?