Why are we not allowed to kill

[ICantSpellDawg]

Well, the trite response is: would you personally like to be killed or in fear of your life every moment?

That has always been the worst and most irrelevant response. Who cares what other people want, realistically? Does me not killing one person have anything to do with whether someone kills me or not? Probably not. In specific instances that rationale would make sense, such as when you are in a room full of people who want to kill one another. Most of the time you killing someone wouldn't impact whether or not you are killed, so the question is irrelevant as it relates to its inherent immorality. To do that you have to find out where your specific moral code comes from.