It's not just Russia who is willing to overlook Voynov's actions.
Kings wanted him back too, they underestimated the public backlash from fans/NHL.
http://abc7.com/sports/la-kings-fined-$100k-after-slava-voynov-skates-w--team/418932/
After they got caught, they issued an apology and later had their players sit through a class on how not to beat your wife. Definitely a PR stun. They wanted him back on the team.
A couple of corrections:
The Kings were caught letting Voynov into team practices while Voynov was still in LA. Your comment implies Voynov was already in the KHL when the Kings asked him to practice with them.
The Kings announced a series of classes on domestic violence before Voynov was caught skating with the team.