Unless you are like 80 years old, hiring coaches that played for rivals is nothing new. If schools only hired their own alumni to coach, there would be a lot of unemployed coaches.
Oh wait, WSU hired one of their own. How'd that work out? They ended up eating their own.
I'm sure USC alumni were really pissed when Oregon Duck alumni John Robinson lead them to a national championship.
The list goes on...time for a reality check.