If Tim Raines wants to snort coke after a game, that's his business. If Pete Rose wants to throw a game in order to line his pockets, that's the business of Major League Baseball.
Luckily for them, they didn't have to. Maybe if they had lived in the 2000's, you wouldn't have seen Ty Cobb drop kick a guy in a wheelchair.
Show me a guy who has been banned from baseball for being a drug addict. I'll show you twenty who have been banned for being associating with gamblers.
This rule wasn't invented yesterday; it's been around almost as long as the game itself. Rose knew that he could be banned from baseball if he placed a bet from baseball. He did it anyway, and he's getting what he deserved.
Though, if MLB wanted to induct him into the Hall of Fame, and on his plaque it said, "Permanently ineligible for gambling on baseball," that would be fine with me.