I.e. if people will not “ban” misbehaving political organizations from their personal affiliation, it is certainly fatuous to talk about banning them by some other action. The freedom of politics includes the freedom to invest politically in evil. If this freedom did not exist, we would not have freedom to invest politically in goodness either. “Goodness” would be forced, and soon cease to be goodness.
MLK Jr. isn't the only one who can dream.