Charlaquin
Goblin Queen (She/Her/Hers)
It’s true, but this advice is only helpful if the group actually uses XP, which it seems so few do nowadays.This.
Players kill because that's usually the easiest, most straightforward way to achieve their goals. Put a XP reward on top of that and the decision to kill becomes a no brainer.
If you really have a problem with all the killing, you just have to offer alternative ways for the party to handle obstacles.
That said, I would also like to point that there are systems better suited to that play style than D&D.