Check out the faa page Getting Started Chart clearly makes the distinction between hobby and Part 107 altitude limits. one of the community based organizations recognized is the AMA and their safety guidelines only limit flights to below 400 ft when within 3 miles of an airport.
This is one of the issues with the AMA.. they want to make it look like their Association is much more than it is. What is a "Community Based Organization"? The FAA only states that the AMA can be one. What this really means is that a local organization can set rules, within the FAA regulations that regulate operators under their control. For example, lets say the AMA sets up a flying area or a competition. Part of the rules for operating on their managed property is that flyers not fly faster than 25mph. If you want to fly at that location or be a member of the AMA at that location, then they can set those local rules. However, because the regulations allow a CBO to set rules in _no way_ makes those rules apply to people that the CBO has no control over. For example, the AMA can make a rule that no one can fly above 10' or faster than 2mph. That rule would only apply to AMA members, the AMA does not make national regulations or laws. They have _no control_ over non-AMA members and people not operating on property under AMA control. The AMA only states that the FAA has ruled that the AMA is a CBO. That is fine... but it really does not say much.