Buddha technically counts as a God, because everyone that reach Nirvana become Buddha/one with Buddha. I know it is a state of enlightenment, and that the "first" Buddha was Siddharta Gautama (and therefore indicates that Buddha is just a human being with greater understanding). However, isn't reaching heaven, or paradise, in other religions practically the same deal? God's heaven. Nirvana. The difference being that Buddhism demands more of you to reach it. Hinduism "simply" encompasses all of these as different interpretations of the Brahman.
I agree that calling Buddha a God is, by common understanding, wrong, but in order to mention the five large religions, without going into details, naming him along with the other, more accurate Gods would seem the shortest way around. Pardon me if I offended anyone.