This is an interesting history of the NRA. For most of it’s life the NRA was concerned with promoting hunting and shooting sports (i. e. target shooting). A group of “gun nuts” took the organization over in the 1970s.
There is a universal human desire to avoid conflict. Moderates stay uninvolved because they have neither a motivating passion or the heart to challenge those at the edges. It’s very easy to radicalize an organization.
If the reports are true that most NRA members do not support their leadership and that there has been a climate change in gun control attitudes, then now is the perfect opportunity for the moderates to take back control of the NRA.