How do you explain why the brain washers themselves are left in the first place, or how the left brainwashers are doing a better job than the right?
My speculation regarding the brainwashers is that they were originally left to a normal degree (the typical democrat) and in their zealous patriotism slid into an extreme without consciously considering, or preferring to deny, the consequences of their "open-mindedness". My apologies for the distasteful analogy, but the Dems remind me of the toddler with a soiled diaper who's mother can't convince him to let her change him. In his mind, it's warm and it's mine so I want it.
Or, in keeping with the times / current trends they unwittingly evolved into extremists? Who knows?
As for the left being more successful in their brainwashing, no doubt the mainstream media is a tremendously influencing factor.