I wonder if that's because in the Old Testament, the book Jonah is followed by the book Micah (sounds like Michael). So if you've ever heard/read the books, it would be Hosea, Joel, Amos, Obadiah, Jonah, Micah, Nahum...just a theory.
My oldest is a Jonah! His middle name is an old family name...one syllable and I think it sounds great. Other names we considered were Gabriel, Mark, William...it's been 6 years, can't remember any more.