While insensitive and rude, I am not so sure that the comments, in context, can be classified as "ignorant."
Imus first describes them as rough, then as tattooed hos, and finally as nappy headed hos.
The Rutgers team was indeed a much rougher and more physical team than most women's teams I have seen play. There were definitely tattooed girls on that team. And, I would say that every person will have nappy hair if they play a full 40 minute college basketball game (most likely, their hair will be nappy by the 15 or 10 minute mark in the first half.)
Really, the only real word in question is "ho".