Is Christainity Evil????

The Bible says thou shall not kill, so why did the christian church take it upon themselves once they had became linked with the Crown & Govenment to erradicate all earlier beliefs? They called the gods of the nature religions devils & demons and accused there followers of laying curses & practising foul magic then hunted these poor people down, arrested them, sacrificed them, executed them, then brang in special laws to cover their crimes. Incentives in terms of land & money of those convicted were provided to encourage people to report their neighbours and fellow villagers. Can you really say that this is a GOOD religion to be apart of???