Why does it have to be more than a coincidence? He was a personable officer from a country the CSA was desperate to impress.
Oh, they did, it's just that the SecNavy was just terrible at dealing with an enemy cruiser. As Semmes explained:
the old gentleman [Welles] does not seem once to have thought of so simple a policy as stationing a ship anywhere. The reader who has followed the Alabama in her career thus far, has seen how many vital points he left unguarded. His plan seemed to be, first to wait until he heard of the Alabama being somewhere, and then to send off a number of cruisers, post-haste, in pursuit of her, as though he expected her to stand still, and wait for her pursuers! This method of his left the game entirely in my own hands.
Yes, though in that case she wasn't even a purpose-built commerce raider (she was just a ship under construction which the CSN purchased in secret) making it even harder to tell that she should be stopped.