Not the op you responded to.

But

First 72% is actually a huge turnout compared to pretty much any vote in the last 50 years.

The 28% that did not vote cannot be used to argue either side of the vote. As such they must be assumed to divide as the vote was.

Same with 1.9 % spoiled ballots. As we do not have any legal none of the above option. You have absolutely no way to decide that 1.9 % between those who support or don't. So again statistically they have to be divided as those who successfully voted are.

This is exactly why we do not count non voters or spoiled votes when deciding on an election. If 1.9% was significantly higher then other election or 72% significantly lower. Maybe some data might make sense. But the result would still be the same without further info. You would still have no ability to use them as a rejection or support for the vote.