Don't forget that back then, DWI wasn't a death sentence. In 1972 I lost my best friend to a drunk driver, it was the 72nd time the asshole had been stopped while drunk. MADD killed off the fraternal organizations when they got stricter laws passed, hard to get to the meetings without a driver's license.
Before MADD pushed drunken driving laws, fraternal organizations were very common. Elks, Eagles, Oddfellows, and a bunch of others used to have places men could go to gather for drinks and conversation. Most of them did and do fund charities to keep a non-profit status. The Flintstones were a reflection of the time they were made, so Barney and Fred belonging to a "lodge" was normal and expected.
By definition an assault rifle is capable of fully automatic fire. AR-15 is semi-automatic.