The fear imposed on southern blacks by the Ku Klux Klan was far worse than the institutionalized fear of Jim Crow laws. Jim Crow was bad and unfair but the Ku Klux Klan actually intentionally killed black people. The fear of dying is stronger than the fear of not being able to use the same bathroom as another person.
It is hard to measure the difference in the awful oppression of the KKK and Jim Crow laws. However, the KKK answered to no one in their brutal and violent terrorization of not only blacks, but Jews and anyone else who dared to stand up for human rights. The lawlessness of the Ku Klux Klan is what made them so dangerous. In addition, there were respected white community members, who donned the white sheets to join in the violence. Laws, such as the Jim Crow ones, can be fought without violence and struck down. There was not much people could do to fight faceless terrorists.
As bad as the Jim Crow laws was for blacks, the fear imposed on southern blacks by the Ku Klux Klan was way worse. Black people in the south not only had to worry about not being treated like human beings, they also feared for their lives and safety because of the Ku Klux Klan.
The Ku Klux Klan terrorized blacks, often killing them, while the Jim Crow laws mainly had blacks separated from white people. Each race had their own areas to go to. Segregation alone doesn't sound as bad as past treatment of black people otherwise where they were denied privileges/rights, and where I'm sure services they received from whites were sometimes sabotaged and getting their problems resolved was difficult. Although I'm sure the black people's locations were inferior to white people's.
I believe the institutionalized fear of the Jim Crow laws were probably worse than the fear imposed on southern blacks by the Ku Klux Klan. While Ku Klux Klan was devastating and obviously much worse if encountered, they did not affect all blacks as the Jim Crow laws did for decades.
No, the fear imposed on southern blacks by the KKK was not worse that institutionalized fear of Jim Crow laws, because when something is institutionalized, it is done with that much more force. We all understand when a few fringe people want to act inappropriately, but when the government does it with the power of enforcement, it's that much more fearful and insulting.
Of course the KKK was a more Nordic-style terror group, but believe me, the effects of being institionally franchized are just as terrible. Crime-ridden neighborhoods, and eventually one where gangs roam free. Living your life in terror of gangs. So both are ahborrent. Both worse than the Nazis or Fascists if you ask me.