And now, another installment of : "why are people so frickin"?

I've received quite a few of those myself. The reason is this... You are attempting to interfere with another individuals ethics. By doing that, you are challenging their upbringing from childhood, and in some cases, their strong belief structure. If one was to come up to you, and challenge what you feel is correct, and you've felt it was correct from your first logical memory, how would you react?