But when you spell it ad hocracy it looks like the word is hocracy and you are somehow adding to it.

With respect, it does look like "hocracy" and you are adding to it ... which is just exactly what is intended.

The play is on the words "ad hoc": two separate words without benefit of hyphenation.

Anyone who doesn't get "ad hocracy", doesn't get "ad hoc", so the play on words is lost on them in any event.