If God exists and He is the cause of truth, beauty and goodness then His death would remove those qualities from human experience.
If God does not exist then truth, beauty and goodness cannot be caused by him and so their existence in the human experience cannot be dependent on His existence.
These are crayon sketches of two possible positions regarding the relationship of virtue to the existence of God.
In a post on the painter Francis Bacon at OpenDemocracy the author confuses these two positions. Specifically they confuse the preconditions of the former with the consequences of the latter.
They find the exemplification of this mummers’ atheism in the painting of Francis Bacon. Bacon cannot be touched by the grace of God for a very good reason that they neglect to mention for some reason. Despite this, Bacon treats both sacred and profane subjects equally in his art. This is an a-theistic art (rather than an anti-theistic art) but it is not a design for life for atheists or the only possible experience of a Godless universe, even for Bacon.