If it's been interpreted to say more than the text says on its face, all you have to do is point to that authority. I'm not saying it hasn't been, just that if you're positive it has been, so just cite something.
Interpretation: Article II, Section 1, Clauses 2 and 3 | Constitution Center
Interpretations of Article II, Section 1, Clauses 2 and 3 by constitutional scholars
constitutioncenter.org
Historically, there has been an even more dizzying variety in the systems developed in each state. In the first presidential election, five state legislatures—in Connecticut, Delaware, Georgia, New Jersey, and South Carolina—themselves simply designated presidential Electors without having any popular election at all. In four states, the voters elected all of the Electors. In Virginia, which had ten congressional districts, the General Assembly divided the Commonwealth into twelve presidential districts and conducted a popular election.