Being a bit of a low time guy, especially in seaplanes, I am trying to understand some of your comments.
First off, my condolences to friends and family, sad day.
As I watch the videos and read the 'witness' reports, the statement that creeps into my mind "what is he doing?" Non-pilots, especially guys that have not been around float planes, have zero understanding of what a 'normal' maneuver would be.
As I watch the footage of the flight, I see a plane making a turn onto a final for a low approach. The plane appears to be making steep banks, but I see a 30 degree bank and some optical illusions due to the sun making it look steeper.
Next I see a low pass over a landing area. Looking for wakes, logs, wave size and swell I would imagine; seems a great idea to look before landing.
Next I see the plane come back around, can not say that the bank is as steep as some seem to think, but for sure the sun reflection changes the appearance.
The execution of the touchdown resulted in a bad situation. Why? can be many reasons including a damaged hull prior to touchdown.
I am not so sure this guy was hotdogging, seems to me he was trying to make a landing, did a prudent fly over of the landing surface, (do you look over your landing areas prior to landing?), and made a second approach for landing. Non-pilots opinions and commentary should be ignored. Come to think of it, beginners like myself should be also.