To start, Wie is a sponsor's exemption, so she is not taking anyone's spot.
As for women playing in the PGA, it's the same old arguement as last year with Annika. The women have their own league that men are not allowed to participate in, so does that mean that women should not be allowed to play in the 'men's' league? Or isn't the PGA the place for the best 'golfer's' in the world, so why can't women play?
Just as last year with Annika, this is a publicity event. It can do nothing but good for the PGA, LPGA and Michelle Wie. People will watch the Sony Open to see Wie compete against the men. If they are impressed by her play, which they will be, they may watch her on the LPGA. If they follow her career, they will buy her line of clothing,
clubs, etc.
It's not like there is a woman being exempt every tournament, so who cares? The women who are good enough to compete in the PGA know they can make WAY more money on the LPGA than on the PGA because they can win tourney's frequently on the Ladies tour, where as they would frequently miss the cut on the PGA. I'm not saying they couldn't win a PGA event, just not as good of a chance because of a MUCH stronger field on the PGA tour.