It's a simple answer because lfg elitism isn't why Ghorn is getting nerfed. If they wanted to fix that they'd add in game matchmaking. A full team of Gjallarhorns blaze through content, fully exposing how artifically difficult high level pve activities are. So they nerf Ghorn to make players take their time and their bullet sponges seem to be actually challenging. More time in game. In fact the fewer people that have Ghorn the better because that's a lot of endgame activities you have to grind for it. If increased lfg elitism is an unintended consequence then they won't care as it only benefits them with more players grinding.