“How has the gold become darkened, its finest color changed?” 
The evils of relativism are everywhere in our society and shock upright souls who have a very lively sense of the contrast between good and evil.
(Saint Paul: “Preach the word: be instant in season, out of season: reprove, entreat, rebuke in all patience and doctrine,” 2 Timothy 4:2)
Today, wishing to blend good and evil in one pot, as the secularists wish, is seen as a manifestation of wisdom; it is as if one made ‘a puree with ground coconut, ground nuts, peanut butter, ground almonds and ground cashew nuts, turning it into such a homogeneous puree as if the whole thing had become only one substance,’ and thus abolishing ‘all differences between good and evil, truth and error, personal and national characteristics.’ 
This image describes secular relativism quite well!
Seeking to maintain the distinction between good and evil has now become censurable.
There is even a kind of epithet to disparage those who call good, good, and evil, evil, and see them fighting each other: “You are a Manichaean,” they say. What a supreme horror!
With this they try to instantly “freeze” non-compliants.
The Manichean epithet is endowed with a certain electricity that seems to fulminate the person designated as such.
Now then, from the very early dawn of time, distinguishing between good and evil has always been deemed necessary.
And therefore, long before Mani, who started Manichaeism in the 3rd century. That distinction is a precept of natural law, God established it in the Decalogue, it is found all through the Old Testament, was preached by Our Lord Jesus Christ and is part of the doctrinal and moral patrimony of Holy Church.
In a certain sense, to deny the opposition between good and evil is the height of immorality, as it constitutes the essence of moral relativism, which is the real danger.
In it there is a lack of definition, sense of dignity and direction.
Sacred Scripture speaks about that opposition all the time: “Good is set against evil, and life against death: so also is the sinner against a just man. And so look upon all the works of the most High. Two and two, and one against another.” 
(Based on and adapted from informal conferences given by Prof. Plinio Correa de Oliveira.)
 Lamentations of Jeremias 4:1.
 Manichaenism sustains that the universe was created and is dominated by two antagonic and irreducible principles: absolute good, the “good god” and absolute evil, the “bad god.”
 Ecclesiasticus 33:15.