Their linguistic ancestor appears to have been good old 'PC' that meant being 'Politically Correct'. That was driven by the fear of offending someone else who was sensitized to TAKING OFFENSE. Thus the art of victimhood as a winning strategy was born! With no surprise, the origin of PC appears to have derived from the 1930's Communism where a humorous, but telling, quip became popular;
“Comrade, your statement is factually incorrect.”
“Yes, it is. But it is politically correct.”
One thing I will note about this acronym of 'DEI', the small but interesting coincidence that "Dei", as found in such phrases as "vox populi vox Dei" (the voice of the people (is) the voice of God), is the Latin word for God. Wonder how that match just happened? [SARCASM]
Jordan Peterson reorders the acronym letters to "DIE."