kov,
Actually, having coached myself for several years, it is 'far' from stupid to have coaching defenders be easy while coaching attackers is hard. Defense is largely position oriented and mental. It can be drilled and prepared, to a large extent, ahead of time. Any half-competent coach can prep a defense. That's why you see so many coaches do exactly that and why commentators treat defensive gaffes as coaching mistakes. By and large, they are. Any person with half a brain can prep a defense and make competent defensive players.
Attacking football takes improvisation, adaptation, and a much higher skill level on the ball. It also takes a 'much' more patient coach. Defensive results are fairly quickly taken in. But 'teaching' players to be more creative takes a 'lot' of time. This is especially true if they've never been allowed to be creative before. It is 'much' more difficult to coach attacking football than defensive football, and attackers than defenders.
GKs are in their own little world, you either know how to coach them of your don't. Having been a GK when I was a player, I have a clue.