I understand what he's saying... I don't agree with his tone, but it's true. Most guards in the league will not get around solid screens no matter if its Dwight Howard or Kwame Brown. That's why support is so important on screen and rolls. It gives the screenee time to recover while trying to get around these huge guys because no matter how quick or agile, they're not getting through a well established and well used pick.
Most PGs are bad defenders, the good defensive players at PG know that if your a good shooter you go over the screen if your a bad shooter you go under it. Fisher essentially made Nashs life difficult when he would fight over screens forcing nash into the paint where he's not AS good
Nobody is saying run full speed into dwight howards chest. Fight over it or under it based on the opponent. Simple.