https://founders.archives.gov/documents/Madison/01-10-02-0065
There was one difficulty however of a serious nature attending an immediate choice by the people. The right of suffrage was much more diffusive in the Northern than the Southern States; and the latter could have no influence in the election on the score of the Negroes. The substitution of electors obviated this difficulty and seemed on the whole to be liable to fewest objections.
The electoral college was designed from the start simply to let southern states launder slave votes.
The first time the south lost control of the presidency, they rebelled in the Civil War, and they've used it to get the presidency or otherwise get power dozens of times.
It's something the south feels entitled to, an override over the government because they are "The Real Americans" as they wave their confederate flags proudly.