I believe there are absolute wrongs and absolute wrongs. There's been some disagreement in history about what's wrong or right, and some values definitely change as we go along, but I absolutely believe that killing is always wrong. Stealing is always wrong. Cheating on your spouse is always wrong.
No matter what situation you find yourself in or what condition, it's always wrong to do these things. Killing is wrong, even if you have to do it to wage war or defend yourself from a threat. Stealing is always wrong, even if you're poor and are starving and have nothing to eat. Cheating on your spouse is wrong, even if they abuse you and beat you. Of course, sometimes we do what we have to or to get away from even more trouble, but that doesn't change what's wrong.
I believe in the Golden Rule, which says, treat people the way you want to be treated, love others the way you want to be loved. And whether you're religious or not, you find that rule everywhere, in every religion, in every political system on Earth. I believe that this is because there is an innate conscience within us which pushes us to love others naturally and do the right thing.
Christians, like myself, believe that since we were created in God's image, we were made to love just like He loves us, but that's another topic for another day.
It gets difficult when it comes to controversial things like abortion and homosexuality, because there's so much hatred and fear and disagreement among different religions and religious denominations. It's hard to tell people to mind their own business when it comes to society and religion, because for most of these people, religion is their life. You have to understand that and find a way to convince these people not that we should keep things separate, because they can't, but that perhaps their own religion doesn't see things as strict as people often interpret things.
What's wrong with killing? humans kill animals everyday, animals kill other animals, the entire ecosystem operates on killing. Part of the reason why people form communities and groups in early human history is to provide each other with protection against killing.
Stealing is connected to the concept of ownership, which is non-existent outside society, if you are stranded on an island, would you care if the fruit you pick belongs to a money living in the tree?
Our morals are very delicate things, society gives us alternatives to law of jungle when it comes to living, but that doesn't make the law of jungle wrong. In fact if society breaks down, in order to protect so called "properties" killing or threat of death will be necessary at all time.