Hey, Bubba, the particular Hitchcock story I remember appeared on TV, and it was probably one of his Alfred Hitchcock Presents episodes. I don't remember having seen many Hitchcock feature-length films (Psycho, The Birds, North by Northwest); if this one was a feature-length film, I don't recognize the title.
The story I remembered, and looked for, involved a young couple taking refuge in "any old port in a storm" in an ancient and decayed plantation-house out in the swamps, which in turn were infested with scary boogermen. White scary boogermen, of course. If they'd been black, that would have been racist, wouldn't it?
Take a look on IMDB.com under his filmography (TV); they list all the episodes there. In particular, look at Season 2 Episode 12, Season 4 Episode 4, and Season 5 Episode 13, and Season 5 Episode 15 for Hitchcock's use of Southern stereotypes.
He uses other stereotypes as well: London fog, London inspectors (both active and retired), returning veterans, Chicago and Brooklyn hoods, Western prospectors and miners, and a whole cast of villains-next-door. But where he portrays Southerners, they are almost always guilty parties, boogermen (or in the case of the first episode listed, boogerladies), and what have you. Whereas others may equally have been victims as victimizers.
Granted that Hitchcock made much more use of other cliche's and stereotypes (blonde women/"ice goddesses"), but he did use the sweaty Southern boogerman stereotype.
By the way, I'd call your attention to Season 5, Episode 12: it's the "Lamb Armistrand" classic, entitled "Specialty of the House". Very memorable.
Very thorough. I’m impressed.
And this is sufficient for you to come to the conclusion that "Hitch hated Southerners with a passion."