If there is such a thing as a Creator God -- what are they arguing against if there's not? If there is such a Person, then He gets to define what is moral and ethical for us, not the other way around. We have no right to tell God what is repugnant or virtuous; He tells us what is Good and what is Evil. If we don't like His categories, tough.
Furthermore, it is the nature of a supernatural God that His logic is better, more perfect, than our limited mortal reasoning. If we do not understand how His ethics work, or if we see inconsistency in it, whose fault is that? Even the atheists admit to the possibility of an older race "out there someplace" in the universe with better ethics that we could learn from, because their wisdom and experience would exceed our own. How much more so if the alien "race" is God Himself?
All of these militant neo-atheists grew up in a culture dominated by Christian values and morals, and they mostly adopted those Christian values unknowingly, long before they were old enough to know what they were doing. Because they did so unwittingly, their value system is ungrounded in any logic or reason, and has numerous inconsistencies -- but it is essentially Christian nonetheless. They are arguing flawed Christian ethics against the perfect Christian God.
A good atheistic perspective has no morals because it has no god to
enforce them. Sometimes they admit to a "nature red in tooth and claw,"
but rarely do they acknowledge that all Darwinian ethics are unalterably
selfish, without any social virtues at all. Unfortunately, the real world
does not fit the Darwinian model in many ways, this being only one of its
flaws. The atheists are compelled to explain the existence of social virtues
-- and they try -- but they cannot, because altruism (sacrificing personal
benefit for the good of others) only confers survival on its practioner
in a culture where the majority already carries the altruistic genes. Otherwise
the first carriers of such a mutation die out before passing their genes
on to the gene pool. The bottom line is that an atheist arguing ethics
is an oxymoron. The very nature of atheism and Darwinian values-free survivalism
implies that nothing they say can be trusted beyond what can be independently
verified.