This is easily resolved by adding more sound channels to your game options.
There are soldier sounds especially in the 2nd campaign.

But the idea of the your own mic being heard by the enemy is pretty cool idea.

If you're like me I tend to put my vid card settings down to high performance on nvidia.
Have you tried switching your graphics card settings outside of Arma 3 to something slightly higher than the lowest option?

Okay here's what you need to try - get all your squad to go into STEALTH mode.

For some reason if you don't do that your NPC players will have a bad habit of wanting to shoot at the helicopter even if you put them in prone.

So STEALTH and HOLD FIRE squad options.

I did this within less tahn 50 meters of the helo landing and didn't get detected this way on both saves.

After 3 saved game tests - the helo always has a habit of landing it's nose towards the south end.

So if you blow smoke north of you the helo will see you. Blow smoke south of you far enough AND your team is down in prone in stealth then he will not see you.

I got him to land on an explosive charge that I saved from one of the earlier missions and he was down.

As it's great to have to the equipment you brought back remember the name of the campaign - Adapt.

Did you know the Taliban and Al Queda would love something like to train their troops? Use a game with real or simulated hand signals and use that for training?

I had the same complaint before but think of the security situation the real world is in right now.