Oh dear we are back to that bitter note again.
If they had been military pilots I would be equally critical.
The fact that they are nice guys is irrelevant too as is much of the guff about hours and training - when you fly a perfectly serviceable helicopter into the water because you weren't paying attention to the IAS (and kill several pax) you can blame as many of the contributory factors as you like but the main cause is pilot (both PF and PM) error, plain and simple.
In these times of Covid and brexit it is comforting to see that some things never change.
Anyway back to the point, the cause was as you say, and as the report says, pilot error. The pertinent question for anyone not living in a 1960s aviation culture, is why did they make that error. I have tried to address that question but it seems you aren’t interested.