It isn't just because of the lockouts that the viewers have dropped, have several big names tested positive for steroids countless fans felt cheated by the stars of the MLB and didn't know if they were cheering for the player or the roids. The NHL does not have the same problem (yet it could happen), the lockout may piss off fans but most come back as they still love the sport.
Great point and another reason that a lot of baseball fans despise Fehr. He was perhaps the biggest voice against drug testing and anti doping policies. I remembered him likening it to someone showing up at your door and testing you. Civil liberties, privacy, and all that stuff. He completely ignored baseball's rich history and the integrity of the game.