I'm not arguing for a right to dehumanize; I'm arguing for a right to hold such views and express them.
The undemocratic parties were as you say, elected via democratic means. It was only once they were in power that they revealed their true nature (though admittedly, a few did have suspicions beforehand). Prohibiting anti-democratic parties hardly does anything. It is doubtful that parties running on such a platform would ever be elected in a democratic system. The prohibition doesn't target the real problem: parties that get into power and then become drastically undemocratic.
The undemocratic parties were as you say, elected via democratic means. It was only once they were in power that they revealed their true nature (though admittedly, a few did have suspicions beforehand). Prohibiting anti-democratic parties hardly does anything. It is doubtful that parties running on such a platform would ever be elected in a democratic system. The prohibition doesn't target the real problem: parties that get into power and then become drastically undemocratic.