Morality may be relative by some definitions, but no attempt to convince me that wrong is right will convince me that doing evil is Good. The faculties for Goodness are the same for evil - knowledge and action. It is when we rationalize evil behavior with "good intentions" that we weaken our sense of what is Good.
Given the choice between right and wrong, it is easy to do right when you are treated rightly. This knowledge bears a duty. Doing Good requires taking responsibility for your actions and having a strong enough faith in others and the power of the Golden Rule.
I think an Objective Morality stems from the Golden Rule, but I haven't a clue how to prove it. It just seems so obvious that is Good to do something for (or to) someone else that you would want someone else to do in return - and a moral man perceives no difference in the joy and suffering for all involved. Do not aggress against others because they possess wealth and do disregard others when they find themselves destitute. Any action (or inaction) that is not in accordance with the rule is less good than one that is - I'm convinced that is an objective reality. I think all individuals observation of our collective actions reveals this if we are honest with ourselves.
Justice requires we stop doing to what others don't want us to do, even when we think we're doing it for their own good. Being considerate of others leads to seeking their consent and sharing our opportunities. We reap what we sow. If you believe you are in a case where the Golden Rule does not apply, you simply have not exptrapolated the rule far enough. It is much better to live and let live, in short to forgive, than to kill or be killed. The former is divine while the latter is hell.