Referendums are seldom used in the UK. This one was not legally binding.
Legally a referendum only has the effect that Parliament decided. In this case: none.
Parliament is sovereign and it voted to leave the EU. Its decision was informed by the referendum but it was not bound by it, nor did it have to take any action at all.
The decision was political because it was untenable politically for Parliament not to vote to leave the EU considering the referendum's result.
There is little point in revisiting this mess outside history. The EU is not about to ignore the actions of the past 2 years because the UK finally figured out it is corrupt. The deal, for better or most likely worse, has been done. No taksybacksies says the EU.
Legally a referendum only has the effect that Parliament decided. In this case: none.
Parliament is sovereign and it voted to leave the EU. Its decision was informed by the referendum but it was not bound by it, nor did it have to take any action at all.
The decision was political because it was untenable politically for Parliament not to vote to leave the EU considering the referendum's result.