Najdorf 6. Bg5 h6

It's obvious that h6 is bad here. In fact, it's so obvious that I can't find anyone who clearly explains why. chessgames.com only has 3 games with this response, and all went to at least 25 moves. So it's apparently not an immediate-death type blunder.

7. Bxf6 gxf6 8. Bc4 looks good, of course .. but even that is only in 1 of the 3 games.

In Nunn's book on Bg5 he says "moves which can be refuted with the aid of general principles and a little common sense are not mentioned in this book" but he even gives a quick mention to 6. ... e5

I guess my question is: as a beginner, where arethese moves mentioned? chess.com forums? ;)

i know this very well it is good for white caz of bxf6 exf6 qf3 and white is much better