"Why?"
Thank you for the question, Verlaine. As for my indefatigability (good word, by the way) I am doing this, first because God asks me to and second, because I truly love these people and hope to reach an understanding and mutual respect with them. My best friends are atheists. Me and many Christians don't seem to get along. Too much blind faith and dogmatism on their part for my liking.
"I suppose it could be an argument about semantics, but I, as an atheist, certainly don't think that morals are inextricably linked to religion."
I don't think so either - and neither does God. But if morals come from culture or evolution than must accept other cultures who don't share our some values. Thus, in China where mothers are strangling their infant girls, the consistent atheist is forced to say, "I don't like it but it's not objectively wrong." I respect logical consistency from atheists - even when I disagree with them.
"I think that morals can be linked to society and humanity and civilisation. " Of or concerned with the judgment of the goodness or badness of human action and character ". to quote one of the on-line dictionaries."
Not to help you make your case, but I were you, I think a better case can be made for morals coming from evolution. But they are still somewhat arbitrary as Dawkins admits.
"If we live in a community we make judgements about the goodness or badness of human action and character. WE make the judgements, and as an atheist, I make a judgement (which I might or might not make public) without reference to God or Gods."
Yes, but on what basis do you make those judgements? CS Lewis, who was an atheist-turned-Christian due to this very argument, "Said how can man know a line is crooked unless he knows what is straight."
"And "no free will"? What is your reasoning for that statement? Surely we do indeed have free will. We make decisions which will be influenced by our culture and upbringing and possibly our genes, but we do make decisions. No-one else makes them for us, do they? Well, they might, but we can tell them not to or vote them out office."
I have posted links above. A logically consistent atheist would say that all of our choices have been predetermined from the beginning of time. Recent lab experiments indicate our brain reacts a few seconds before we are conscious we made a choice. And here is a quote from atheist William B. Provine:
"Let me summarize my views on what modern evolutionary biology tells us loud and clear -- and these are basically Darwin's views. There are no gods, no purposes, and no goal-directed forces of any kind. There is no life after death. When I die, I am absolutely certain that I am going to be dead. That's the end of me. There is no ultimate foundation for ethics, no ultimate meaning in life, and NO FREE WILL for humans, either." [Emphasis mine.]