I'd like to take a moment and thank God that the majority of non-Christians don't live consistently with what they believe.

Or you can derive your moral system from a made up god.

Either way, we're at the same place. So... My proposal: we just all agree that mass murder is bad because it's a really dickheaded thing to do to people?

Made up god lol... Why is mass murder a "dickheaded" thing to do then.. Is it just your opinion? Why does your opinion hold more weight than someone who thinks murder is ok? What is you standard in which you measure something to be "dickheaded" or not "dickheaded"..?

BTW, a lot of people think mass murder is ok.... 61 million babies have been murdered since 1973... I think that is a pretty "dickheaded" thing to do to people but other think it is ok...

Because every society that has ever existed has, without exception and regardless of faith and lack thereof, imposed two rules on the common citizen: don't kill people and don't steal. We all agree on it. The exceptions to that rule almost define the differences between societies (things like war and death penalties and who gets to decide on exceptions) but the overwhelming majority of people have to follow those two basic rules regardless of where they live in history and geography.

Your classification of abortion as murder does not enjoy such a clearcut consensus: about a third of people agree with you on a good day. So THAT comes down to opinion and faith, and a restrictive society will impose that opinion and faith on others while a free society would not.

The Brown Shirts were German citizens and the murdered the Jews and stole all of their possessions.

Take your time. It's all there but putting it all together can be tricky when it means shifting the way you've been told to think.

Answer the question and take your time to think about on what basis you can even answer that question.

Don't come at me with that "way you've been told to think" stuff. I wasn't born or raised in the faith; the only time I heard the name of God or Jesus in my home as a child were as curse words.
I was an outspoken atheist until I was 21.

"Every society...without exception" LOL... Nice universal statement... Lets not talk about "honour killings", lets not discuss Viking culture, let's not discuss cannibalism in current cultures like in Papua New Guinea, lets look past 60 million killed babies since '73...

You posit a moral standard and what a "dickheaded" thing to do is then switch and say it's not a "clearcut consensus" LOL... You're having a bet each way... You posit a standard then add a "loophole" to suit yourself.

You might believe "love thy neighbour" and your neighbour might believe "eat thy neighbour"... By what standard are you correct and they are wrong? So far all you have offered as a standard is your opinion and preference... Your standard is subjective at best, based on what "you" feel and your opinion... It is a standard that is not fixed and can/will change as you demonstrated with your murder v abortion loophole....

Why do you have to believe in God to have meaning, purpose, or value?

Most atheists have morals, it's just based on the culture they live in. It's a massive strawman to say that, on principle, atheists have no morals, or are immoral.

I agree, atheists have morals. Some of the best people I have met have no belief in God. The culture they live in is based on Biblical principles though. If the atheist is rejecting the belief in God/creation/etc, then they are accepting big bang/life by random chance - from nothing.

If we are created in the image of God then our value, worth, morality is derived from the Creator and our value to the Creator is demonstrated in the sacrifice of Jesus Christ. If atheism is true then there isn't even a point of reference for our worth - we are the result of random chance..

To quote Richard Dawkins “In a universe of electrons and selfish genes, blind physical forces and genetic replication, some people are going to get hurt, other people are going to get lucky, and you won't find any rhyme or reason in it, nor any justice. The universe that we observe has precisely the properties we should expect if there is, at bottom, no design, no purpose, no evil, no good, nothing but pitiless indifference.”

If atheism is true, the notion of good/evil are merely constructs of our mind (but also how can we even trust our mind/thoughts having evolved from ooze?) and good/evil/morality is based on preferences/opinions - subjective and able to change - there is no standard. If the atheist is honest then killing, stealing etc is not a problem as it is neither "good nor bad" (as that doesn't exist) and is basically one product of primordial slime impacting on another product of primordial slime.

If we come from a blind, pitiless, amoral universe that is neither good nor bad, how can the atheist make a moral judgement? You cant get an ought from an is... The atheist that makes moral judgments about a "supposed" amoral world,(created from a universe without design, purpose, meaning) is borrowing from a Judeo-Christian worldview..

I do give credit to Christian setting up the morals of the western world.