Here is a way to dismantle the moral argument for God without getting into the subjective vs. objective morality debate.
A more traditional take on the Euthyphro dilemma, a classic problem of the moral argument for God:
If God chooses what is good, does God have a reason for the actions to which he assigns a good value? If so, why can humans not come to the same reason? If not, then someone (God, in this case) arbitrarily assigned good and bad values, which is exactly what theists think is the problem with subjective morality.Modern apologists rarely say God decided anything, rather they claim what is morally good is simply part of God's nature. They expect this negates the dilemma. It doesn't. For this reason I recommend presenting a formation more like below to stay with the times.
If God's nature is good and it could be no other way...who made God's nature as such? If someone made God's nature good, then we should probably worship that God...if only we could know why that God made good what it is. There's a potential infinite regress of moral responsibility here which explains nothing. However, if no one made God's nature good, then it's possible for beings to have good natures without a higher being making them as such. Therefore, the same can apply to us.It's a small distinction that most people should be able to come to on their own, but apologists are highly motivated to not think about how their arguments might fail. We need to show them, repeatedly.