This isn't just about a gathering of boats and floats, and it isn't just about alcohol.  It's about dangerous behavior.  We have to have laws to protect people from themselves when dangerous behavior threatens their lives. Period.  These people are extremely lucky they weren't gathering at a beach where lifeguards were not present.  If they had, there would be many dead as a result.  
The regulations enforced at Kaneohe Sandbar were a result of huge brawls and a knife fight that spread to an adjoining harbor.  DLNR enforcement stopped most of that behavior.  Now it's Waikiki's turn.