Used to be many more polls inside schools, with schools in session. I recall the morning "lineup" in the gym kind of in the corner, as we shared the area with the polls.
This promoted an awareness of civic responsibilities, with adults, parents, teachers - interaction with kindergartners thru 6th grade.
Maybe the left wants students to be cut-off from adult/parent models for voting, where it is now mostly solely what teachers have to say about it.
Our still are.