Fair enough, given your background I wouldn't hold it against you for such a reaction.
Being cautious is, imo, responsible. Especially in the world we live in today. Again, I don't hold you at fault for it.
I also agree with your reasoning, being unarmed would be risky, had you not known anything about the person or situation at hand.
This seems entirely robotic to me, exactly what makes work, work. I've been in a work environment that seems fun as well as professional. Imo, that setting makes it more beneficial to me and my coworkers and less hostile to everyone else. You can remain professional without resorting to the dickish, robotic attitude the corporate world requires. Even if your job is in the corporate world.
Regardless, violence is not the way to solve it.
Good luck. Not sure if that'll look good on your existing charges..