AnFI, the accidents and incidents you quoted occurred on twin engined helicopters and not on singles simply because singles are not allowed to carry out the type of work involved. Trying to use such examples to show that singles are therefore safer is totally flawed, false logic. All it can prove is that staying on the ground is safer than flying.
Btw, at least one of the recent tragic accidents you quoted involved pilots who initially trained almost exclusively on Robinson helicopters and most of their flying experience was gained on that type.