Why they need to get rid of organized religion.
Nope. Not really. That's not religion; that's a high demand controlling group that uses religion for a purpose that existed before the religion existed.
Religion serves a purpose in society, and an important one. What should go away is the lack of education around those groups and their misuse and abuse of (in this case) religion.
Also, please note that I have seen similar groups with similar tone, culture and philosophy, causing equal harm (or worse) to others, and they are not religious groups. The issue is not religion, is the misuse of it ill purposes.