I believe that when you read the entire Geist piece along with much of his other work, (see related stories at bottom of linked to page), you see that Geist believes that provided there is proper management of game animals, which includes controls on the number of animals harvested, that trophy hunting as most think, does not ruin the gene pool.
Trophy hunting, as described in the Newsweek article and more accurately written about in the Nature piece, describe trophy hunting as a hunter seeking the biggest rack of horns and/or body mass of the animal he is pursuing. Geist clearly points out that his studies and observation prove that to be wrong.
His own observations as show that in fact the "trophy" animal may in fact be non representative of the strongest of the gene pool and for that reason that's why it is bigger than the others, especially those taken during the rut.
The following link further reveals Geist's discoveries.
"Trophy Males as Individuals of Low Fitness" Please scroll down through the article to find this piece as it was posted by permission from Geist.
The key to all this is that Geist first believes in proper game management. He also believes that overkill to any degree pertaining to any gender or size can cause damage but that it is reversible. Along with that proper management, what most of us enjoy at "trophy hunting" is not dumbing down the gene pool.