Which do not %100 effective, it helps a ton, but adding a suppressor makes it basically completely noiseless to the shooter.
Properly used hearing protection eliminates any damage to your hearing. I'm not sure how hearing protection is not 100% effective when used correctly.
Your logic is, why do you need an airbag when a seatbelt works for 95% of accidents.
This is the definition of a straw man argument.
This makes no sense though, as I stated before, NZ/UK require them. Not only for the hearing protection but also for the noise pollution side of it.
The law/scenario in question is the US. It doesn't really matter what NZ/UK require; are you also arguing for their gun control laws?
People have been shooting firearms for centuries without suppressors, for decades without suppressors but with hearing protection. Saying you need them is flat out inaccurate but it doesn't mean they shouldn't be available to anybody who wants one.