states don't actually choose the president, the voters do

This is not true. Voters only have power because the states give them power. Like I said, and I repeat myself: the constitutional authority to choose the president lies only with the states.

If your argument against advocacy for social or political change boils down to "yeah but this legal document says it is how it is"

The document "says it is how it is" for particular reasons. Those reasons are the basis for an argument against a particular kind of change, not the fact that it simply exists. To ignore that is to mischaracterize the position to which you're opposing. I might as well say, "Well the only reason you want things to be different is because you don't like constitutions or laws," which would be equally absurd.

If you want to make change, you have to understand the system you're in first. It's like they say in art school: you have to learn the rules before you can break them.