Consider the reasons which make us certain that we are right, but not the fact that we are certain. If you are not convinced, ignore our certainty. Don't be tempted to substitute our judgment for your own.
Civilization does not have to perish. The brutes are winning only by default.
You'll come back, because yours is an error of knowledge, not a moral failure, not an act of surrender to evil, but only the last act of being victim to your own virtue. We'll wait for you and when you come back, you will have discovered that there need never be any conflict among your desires, nor so tragic a clash of values as the one you've borne so well.