Talk of referendum's being "non-binding" is a red herring and a distraction.

The Scottish independence referendum was also non-binding, because that is how things work in the UK.

.. Of course there was a complication in the Scottish case as the Edinburgh Agreement (2012) was necessary to hold it, and the UK government was politically bound to honour the result - but that's the same as the UK brexit vote. All parties were politically bound to honour the result, but not legally bound.