leadcounsel
member
A valid concern, but the idea is to remove as much noise as you can from the situation, not all of it. If every rifleman had a suppressed weapon, he would be in better shape hearing-wise and could have an advantage in some situations. They can issue plugs as well, and that will help reduce damage from IEDs, artillery, etc. and further reduce the sound of rifle fire.
With a limited spending budget, suppressors are never going to be provided en mass and there are more effective ways to protect hearing. Like I said before, protecting the hearing is done more efficiently with ear pro because you cannot control other noises such as bombs, machinery, big guns, etc.