First of all chill
Second of all you need to stop having such a high opinion of your of yourself for a few seconds and realize that infesting a school with guns is a bad idea. I know that you're convinced that someone who's passed a test can't possible do wrong with a firearm, but that's def bullstuff. Example: anyone who's ever committed a crime with a legal concealed fire arm. I actually laughed when you said it was a myth that people who carry concealed fire arms never commit crimes with them, that's loving ridiculous. Listen dude, I don't think you're unintelligent, but you have a very narrow perspective about this. Trusting someone to teach your kids and trusting someone to use lethal force around your kids are very different things. Being qualified to teach has no relevance to how likely you are to misuse a gun.
And please don't bring up the second amendment. If you really do think about things intrinsically more then I do as you claim, you would have realized that owning a musket and owning an automatic weapon are two very different things. The world has changed so much since then, and guns are no exception.
Also, if I didn't know which teachers were carrying guns, that would make me feel even more nervous. Like wtf why is it necessary to for these weapons to be concealed? If you're worried about school security, hire security guards with visible weapons. That would certainly do more to deter crimes. Security guards would have little to no interaction with the students, so getting into altercations with them is unlikely. On the other hand, I see teachers getting into altercations with students all the time. Of course in most cases a teacher would never harm a student, I know that, but it would certainly make students more tense if they knew that some teachers were carrying guns.
Teachers don't need concealed weapons. I'm not going to change your opinion, and you certainly aren't going to change mine. Let's just leave it at that.