I do think that outdoor events like going to a protest or the beach pose a much lower risk for spreading
unlike bars/live music venues
like hutchie said, the problem isn't the sand and surf - it's the boardwalks, rides, bars and restaurants around the beaches.
i also strongly believe that folks let the hair, and their guard, down at the beach. you go there to relax and/or party, not to be careful and maintain a healthy dose of caution. i suspect that some folks who wore masks and social distanced the week before threw everything out the window as soon as they heard the words "reopened." they make it a binary choice - full-on war-on-virus mode vs. PARTAY NAKED!!!111 - whereas it's shades of gray, AKA phased reopening (the early stages of which still require masks, distancing, etc.)