Why did they actually make the gun/explosion sounds so weak?

[LucidLocomotive]

I’m wondering if there is a genuine answer. Clearly it was a conscious decision, since the game is so clearly inspired by movies like Heat, which are all the about the loud gunfire and the echo of firefights in the cities, eardrum exploding deafening sound of explosives, etc. 

 

when you look at mods for realistic gun sounds, it makes the game so much more intense. Gunfights like blitz play become unbelievably cinematic. 
 

they obviously had realism and immersion as a goal in mind with this game, so why on earth did they choose to make the guns and explosions so quiet? Is there any real reason for it?