CSK&MI and classical rivals who have fought in so many finals, they have become rivals due to pure persistence. It's the purest form of sporting rivarly like Nadal Vs Federer.

CSK&RCB play the game normally, they have nothing against each other like India&Pakistan Teams obviously do and Rcb is just well RCB, not much of a scary Team like MI are right now. What you're talking about is CSK&RCB fans bickering, that's not rivalry. Teams don't care about that crap so it's not rivalry, Teams MUST be involved in the "rivalry" for it be one.

India-Pakistan and England-Australia are not rivals just because it's of its fans, the Teams themselves are also involved in this rivalry, they sledge and play with passion and make statements like "it's not a game, it's war".