The interesting thing about shotguns is that they don't do that 134 damage all the time. They only do it if all the pellets hit. In terms of TTK shotguns are a one trick pony. They have better TTK than the competition if you hit at least 100 damage, but have worse TTK as soon as you need a second shot.
That makes them particularly vulnerable to spread and damage drop off. This also means that any damage nerf that makes shotguns 2 shots to kill, would render pretty much every shotgun in the game worthless. As they'd just be outclassed by SMGs in every possible way. So no, it doesn't need to be nerfed to 90 damage.
They were just trolling you. Organized squads could likely get similar scores with any gun in the game.