IMO, we need to look wider than the actual activity.
Boating and fishing is just fine... except everyone has to funnel through the boat launch. "oh, gotta hit the bathroom before I get on the water. Huh, there's a line; guess I'll wait my turn."
If a few people sunbathed and interacted with no one else, it would be fine. But looking at the photos, there were a whole bunch of people out. The majority of which probably funneled through parking lots and bathrooms again.
Don't get me wrong; if these restrictions were in place without a novel virus going around, I would be right there protesting too. But sometimes we need to think about people other than ourselves.
If you ever find yourself in a fair fight, your tactics suck.