Two thoughts:

One. I don't find it particularly clever or funny. Sort of hamhanded.

Two: I had understood that parody is specifically allowed under the copyright laws. I expect JibJab would have to pay royalties, but I don't see where anyone could rightfully prevent them from issuing and using their parody.

Trouble is, this sort of harassment is typical of copyright holders, because they know that they have deeper pockets than many of the putative infringers, and the threat of big court costs (even if the parody issuer would be right in the end) can intimidate the writers/performers/publishers of the parody into backing down.

Dave Oesterreich