Chechnya is Muslim. Rather than expelling Chechnya from Russia, or crushing dissent in Chechnya, Putin has fought to maintain Chechnya inside Russia while giving the Jihadist leader of Chechnya almost unbounded power. For example, Then there was that time that Fedor criticized Warlord Ramzan for child abuse in MMA in Chechnya. Ramzan unleashed his holy warriors on Fedor and hospitalized Fedor's daughter. Fedor had to back off. Nice job Putin! Rather than crush the Jihadists, Kadyrov, best friend to putin, has the power to attack Russian Hero Fedors kids.
The Putin-Kadyrov friendship allowed Kadyrov to "allow his subordinates to shoot on sight police/soldiers from other regions of Russia."