Why did Cubs Fans blame Steve Bartman for their teams' failure in 2003?

I, personally, don't believe for one bit that Steve Bartman had anything to do with the Cubs blowing a 3-2 lead in the 2003 NLCS. The Cubs were the ones responsible for losing the 2003 NLCS. A big error in Game 6 along with Prior and Farnsworth's implosion plus Kerry Wood's disappointing Game 7 performance is the reason why the Cubs loss in 2003. When a ball is off the playing field and into the stands, the ball is up for grabs and fans have a right to go for it. That's what Steve Bartman AND OTHER fans did so Cub fans really need to stop with the nonsense. Face it, the Marlins were the better team and they proved it in both the NLCS and the World Series. As a Yankee fan, it hurted but the Marlins were more hungrier than every other team.