Should everyone be treated equally all the time?

ABSOLUTELY NOT! There are some people in this world that are kind of nasty, and obviously, you don't treat them the same as normal people. I'm not saying that you have to be mean back, but just stay away from them and keep them from filling your life with misery and woe... Just saying. Anyway, the same applies for robbers and mass murderers: don't go around being polite to shady-looking people.