If you’re drawing attention from bystanders like that... you’re doing something wrong.
If you insist on flying like that, at least go offshore a bit so as not to make a spectacle/annoyance of yourself.
Had he not crashed and continued to fly like that in the area regularly, I suspect there would be some complaints. Not good for GA../ :/
My Very Humble Opinions:
1. Bystanders are usually idiots. Sorry, bystanders are not pilots, not educated in flying or anything else related to aviation, therefore their opinions are worthless.
2. He's dead, and can't explain what he was doing and why. When I'm in the amphib or on floats I practice flying as low as possible. You need to check for debris in the water. If you don't check, you eventually end up dead. You also need to learn what different water looks like in different light and wind conditions. Slamming into the water because you thought you were higher is all too common.
3. At least one of the maneuvers looks like he is attempting a chandelle. Maybe he wanted to amaze the crowd with a fighter break next time he was at a fly-in. We'll never know. If he has never flown one, or has limited skills, higher is certainly better, but eventually you need to get down close.
4. Is he exceeding the g limits or the manufacturers specs. maybe, probably. But if you don't fly it close to the limits in practice, when the crap gets real you won't have a clue and that can kill you just as dead.
5. He would probably still be alive if he had a competent CFI in the plane to tell him "Dial it back" instead of trying to figure stuff out on his own.
Some absolutes you can take away from this:
He flew outside his personal limits. He probably flew outside the limits of the aircraft.
We are never going to know if there is\was a manufacturing malfunction. The FAA will NOT look that close because manufacturers have money and fight back. Dead pilots don't.
Personal statement:
There is nothing illegal, unethical, immoral or wrong with flying low. I do it all the time.
When I'm in the Cub (or similar aircraft) or on floats, I'm rarely more than a few feet above the FAA required altitude. Flying low is fun.
But it's something you need to practice. Like everything else in aviation.