In this position, White is threatening to play some combo of Bxc5 / Nxe5:
1.d4 Nf6 2.c4 g6 3.Nc3 Bg7 4.e4 d6 5.Nf3 O-O 6.Be2 Nbd7 7.O-O e5 8.d5 Nc5 9.Qc2 a5 10. Bg5 h6 11.Be3
11...b6 is the most popular response. My question is, why not
Nh5, since those moves simultaneously deal with White's threat while making way for the f-pawn to be pushed? Initially, I thought the reason was because it'd be somehow bad for Black if White decided to capture on
c5 and Black had to capture back with the d-pawn. But consider this very similar line:
1.d4 Nf6 2.c4 g6 3.Nc3 Bg7 4.e4 d6 5.Nf3 O-O 6.Be2 Nbd7 7.O-O e5 8.d5 Nc5 9.Qc2 a5 10. Be3 Ng4!
This has an ~80% winrate for Black according to the lichess Masters database, and here he's basically saying to White "please, go ahead and capture my knight! I'll capture back with the d-pawn and I'll be super happy with my position!"
So why is
11...b6 preferred to a knight move in the original position?