That's why CKR exists, because EA fucked up the first time.

They obviously got the thompson confused with one of those little bb machinguns at the fair where you shoot out the little red star. In real life .45s hurt A LOT. You're not getting up after one shot.

A better question is why did they put shitguns in this game in the first place?
It makes no sense, its a boring weapon compared to autos, not as "cool" as sniper rifles, they weren't used in ETO, and lastly they were not in SPR, which is (for better or worse) the template for the game.