Maybe it comes from "Meh!", the Jewish expression for "bored, not interested, don't care, whatever."
Because there's not much to do there. It's at the intersection of Interstate 55 and 255 (the St. Louis roundabout), with a lot of fast-food places, a Wal-Mart, and urban blight as far as the eye can see.
TripAdvisor recommends Chick-Fil-A and McDonalds.
Downtown St. Louis is 13 miles away, so there is a lot of art, culture, and gay activity available. But if you're stuck in Mehlville, you're stuck.
Sounds sort of interesting.
There are two high schools with swim teams, one smiling, the other deadly serious.
Wrestling, with the panther on the singlets going for the crotch. Rather an odd choice.
Quite a lot of bodybuilding.
Ok, now I'm grasping at straws.
Just drive into St. Louis and go to the Bastille.