You have obviously never eaten a triggerfish. Arguably the finest tasting fish in the sea. If it's legal, and ethically taken, then no one will be interested in your complaints. Personally, I don't spearfish for sport, I spearfish to put food on the table. If you want sport, then hunt grizzlies with a switchblade.
Please don't touch the turtles. It's probably illegal, and they're more likely to be friendly with you if you're giving off a good vibe, and not trying to paw them. Turtles that want to be touched will snuggle with you.
I would ask my buddy to be more aware of his gun, and endeavor to do the same with my own.
Some folks are old salts, and some folks are just learning. Most people learn to spearfish by jumping in the water and shooting a fish. Bad habits are easy to pick up, and hard to drop. One of the great things about videotaping your dives is noticing your own mistakes. I know I've learned a great deal about myself and my bad diving habits by reviewing video. It's easy to not be the best diver when you're deep and hunting. Breathing, producing, and retaining excess narcotic gasses (CO2, Nitrogen) while your attention id divided.