I don't see a hint of minstrelsy in those ads.
The fact is, if you're going to have a corporate spokesman, the person has to have some kind of distinctive personality -- like the goofy white "surfer" type who did all those Dell ads before he was fired for smoking weed (iirc), or the "cool" Apple dude juxtaposed with the square Windows guy.
Durrell comes across as a generic, friendly American who is black. I know many Durrell types in real life. I give props to Walmart for creating this character as a spokesman. They could have easily used a generic, friendly white American.
I'm sure black people love you, Miz, cos you treat them like they're normal human beings!!
http://www.blackpeopleloveus.com/
"Mr. Misery always says: 'I'm not racist; one of my best friends is Black!' I think he might mean me!"
Adiolla
(Actual African-American)size>
(Just kidding, Miz. I kid because I love.)