Christ.....
My main goal in citing the racist teacher was to highlight the outlier which is the extremist teacher who may be qualified, and question whether we should arm such an individual. Given the general understanding of wanting to arm teachers who want to be armed, we have not thought about the extremist in this case. The OP alludes that if the teacher is qualified regardless of their belief system which in this case, white nationalism, it should not matter. My argument is thus that anyone who holds supremacist views in a multicultural setting is dangerous. In the case of the link I provided, the teacher willfully deceived the school system and yes you cannot prevent that, but at the same time this teacher kinda gave herself away by exposing her own views. This is the entire point that teachers should not be armed period because we may arm the wrong damn people! Teaching is a stressful job and anyone that is in college or high school knows that these classrooms are filled with stress. Stress in learning the material and stress in expressing the subject matter.
I don't like saying this but sometimes people should not be having serious discussions on online forums if they are going to go extremely left in something so simple.