Slash has always been a rock and roll whore. One of his first opening gigs was supporting Stryper, that’s how he met Axl. He did session work on Insane Clown Posse’s Great Milenko album, and played guitar on two tracks on Michael Jackson’s Dangerous album (does no one else remember the Black or White video with Macaulay Culkin, Slash and MJ beating the hell out of a car whilst constantly adjusting his jock strap)? Hell, he worked with MJ several times after that as well. He sold his likeness to Guitar Hero. He once did an appearance on the Drew Carrey show. Even Fergie does guest vocals on his upcoming album.
So, two points to take from this:
1) Slash is not the arbiter of rock and roll purity, never has been and is therefore not a good barometer for the health of rock and roll in general
2) No matter what Slash does, even if he were to do backing guitars for the 98 Degrees reunion, he is still one of the greatest guitar players who ever lived, so who cares if he makes a buck being a guest mentor on AI?