Why do top players prefer 6. Be3 in the Najdorf?

Why do master players nowadays prefer 6. Be6 to 6. Bg5? I'm wondering if anyone has insight into the thought process of titled players regarding this- maybe a top player themself could answer this best. Do they prefer it because:

A: 6. Bg5 would have given white an advantage, but because the poisened pawn veriation after f5 is analyzed to a draw, there is very little hope to win if their opponet knows most of the theory.

B: 6. Be6 is actually a better move regardless of the theory.

In other words, suppose that neither player knows the theory, but perhaps they understand the main ideas of those two moves. If white is looking for the very best chance of winning, which move might white prefer?