Do atheists even need an objective moral system?

[Tea Earl Grey Hot]

And there really isn't a reason I can see based on non-arbitrary values to be concerned with such things as hypocrisy or credibility. It seems that for all the "good" moral values that most people hold, a person could just as easily hold the exact opposite set of values.

See my previous argument about how not all subjective evaluations are equal. Some can be better supported by logical argument and objective data than others.

To use another example, let's say two people are running for political office, an incumbent for re-election and a challenger. The incumbent will obviously claim to have done a "good job" while the challenger will say the opposite. The public doesn't just call this a wash, that both subjective opinions are equally valid and reality is up for grabs anyway. No, both candidates are then expected to support their case with objective data and reasoned arguments. The one who can support their subjective evaluation with objective data and logic has a stronger case.

The same is true for moral issues. Admitting that morality is a subjective matter doesn't mean all moral codes are equal.

It's still ultimately subjective. Let's say the incumbent did a "good" job at balancing the budget. What if we lived in a society that valued unbalanced budgets (as strange as that sounds)? Then he would have done a "bad" job because he balanced the budget.

That you can use objective data and reasoned arguments to make yourself seem like the "better" candidate is irrelevant because "better" is in the context of how well the candidate follows the desires of the voters, desires which are arbitrary.