Atheism has no genuine moral standards apart from utilitarianism and hedonism. Individual atheists may ascribe to moral truths that transcend utilitarianism and hedonism, but they are borrowed moral truths. There is no sure-founded well-dug well in atheism from which to draw moral truths.
The most careful and thoughtful atheist thinkers and philosophers, such as Peter Singer, pretend to nothing beyond utilitariansim and hedonism. They have seen atheism clearly in its wretched, spare poverty of moral thought and hold its dour vision honest.
There are only individuals -- atheist or otherwise.
It is not true that atheism requires either utilitarianism or hedonism. Rand (an individual) herself subscribed to neither.
I find myself along similar but different objective grounds for atheistic morality.
The question isn't whether you disagree, of course, since you will always disagree. The question is simply whether a reasonable case can be made for an objective morality without need of a mythical diety. The answer is yes.