Is there a reason why Liberals are perfectly fine with so many ridiculous accusations ditto cons made?

I consider myself liberal minded up to a point, turn the other cheek and all that. But how many times must one suffer the humiliation of being slapped? After twenty some years of it I just couldn't understand why the democrats didn't fight as dirty as the repubs do. I think Obama has made some progress in that direction and that is why the repubs are so afraid of him. He's not afraid of them like most other panty waist dems are.