Lions live in a female pride and the males are typically transient. The lioness prefer the male to stick around for a while though and here is why. If a new lion or bunch of lions take over the pride, they kill off the cubs.
Mayawati is doing something similar with the UP police. She is disposing all the SP appointed police cubs. This is bad for UP in case it happens to be a lawless state, but good if it happens to be a very corrupt state. You be the judge as to whether UP is more lawless or more corrupt.
Truth be told, police are recruited on the basis on both political connections and corruption. It would be worthwile watching the caste and religious balance of the new recruits in Mayawati's regime. That would be the true indicator of fairness.