It doesn't seem so devious to me. He wanted Wikipedia to be considered a serious source of information which admittedly, detailed pages for video games, fictional characters and such would work against that goal. Being a non profit also works towards being taken seriously in the eyes of some.

So he created a secondary company to host that content and profit from it. Why not, I would argue. Don't use the product If you don't like it. I personally hate wikia. It's slow and covered in ads. The question I ask is why is there no competition in the space? Jimbo's not on the hook for that.