I agree with your statement, but with almost nothing in the article in which the issue is lost in its complexity. Things are much simpler than that, which is part of the problem.
Objective morality is an adherence to a universal, immutable code of conduct that governs only our interactions with each other. All else is subjective virtue, which churches and states are continually trying to pass off as morality--e.g. going to church on Sunday.
There is no such thing as subjective morality. If there were, genocide would be moral or immoral depending on the majority opinion. That college professors argue for such absurdity shows the irrational lengths people will go to to justify their aberrant desires to have hegemony over others.
As to the question at hand, looking at the reasoned definition of morality rather than the God-given (read humanly "revealed" ) one, it should make no difference what your belief about the existence of God is. You should still adhere to the simple, objective moral code following the principle of enlightened self-interest. IOW, you promote yourself by promoting good order via your own moral example.
Just about every religion came up with a form of the Golden Rule, and then promptly swamped it with "divine revelations" governing all kinds of absurd, amoral/immoral behaviors such as execution for gathering sticks on the sabbath, or the sins of someone being passed on through 4(?) generations. AND THIS STUFF IS STILL IN THE BIBLE!
There's only one moral code, the Golden Rule stated here as: Honoring the equal rights of all to their life, liberty and property to be free from violation through force or fraud.
It makes as much sense for an atheist to adhere to that principle as it does for a religious fanatic, maybe even more--because it's REASONable. And there are only two reasonable positions on the existence of God, atheism and deism.
BTW, there is only one anti-morality, when you remove the equality and universality from the Golden Rule creating a moral double standard (aka subjective morality).
Morality is just that simple.