Mariah is an urban artist overall even if not all her songs are urban.
She's an artist who doesn't need to be pigeon-holed.
The genrification of music in the States has allowed certain artists far greater sway over the charts than their music merits. Why should a Mariah (or any other similar artist's) song garner Urban support from radio when the song isn't in any way, shape or form Urban, and then have that support prop up the position in the chart? It's utterly bizarre.
Personally I'd equalise the airplay on all the major charts and only allow your highest AI from one of the categories to count towards the Hot 100.
213 DAVID COOK The World I Know 8 0 8 0.064
303 DAVID COOK I Still Haven't Foun... 4 0 4 0.023
397 DAVID COOK Sharp Dressed Man 2 0 2 0.026
203 210 DAVID COOK Always Be My Baby 9 10 -1 0.072
348 DAVID COOK Billie Jean 3 0 3 0.069