If morality is relative and based on personal preference, as atheists claim, then their moral judgments of others carry no more weight than if they told you which flavor of ice cream they prefer.
There is an inconsistency here. To claim to know what's right for everyone requires universal moral absolutes. So every time moral relativists declare how other persons OUGHT to believe or behave they are demonstrating their underlying belief in God (because they are appealing to universals we ALL SHOULD believe in) and their simultaneous suppression of that truth (since they claim there is no God) Their beliefs, therefore, betray the confession of their lips.
In moral relativism there are no universal "shoulds" or "oughts" to abide by. If there were it would no longer be relativism.
As an atheist you can be a morally upright citizen but you could also be a morally debauched rapist or murderer - in both cases you are being consistent with atheism. Good or bad are equally evanescent and equally valid expressions of atheism. But atheists often tell me they will do what is best for human flourishing ... but another atheist will do what is harmful to human flourishing. What is the difference? Both are being consistent atheists ... in equal measure. There is no better or worse in moral relativism.
Do I have any examples of atheists espousing moral absolutes?
If you read any atheists online a very significant number of them argue against Christianity by explaining to us how immoral and wrong it is for us to believe it. ... that God is a "moral monster" etc... That we and others ought to reject it because, they claim, God is morally debased. The irony is, in that making this argument, they deny moral relativism and reveal they really do believe in universals --- not just a personal preference, but it is WRONG for OTHERS to believe it too. The irony should not be missed. Such atheists also have affirmations, denials and a missionary force.