To demonstrate the lack of a “clear mandate”.
Yes, Trump will win if he gets one more vote than Biden, but the more he loses the popular vote by, the more justification people have for protesting.
So if he wins on electoral college votes but loses the popular vote by a landslide, at least it shows what The People are actually thinking.
My boss told me verbally “don’t call your colleague a fascist by email or anything else that leaves a record”, so that was nice of him.