I'll give you one clue. It's extremely rare to hold a referendum of such huge consequence.
Heck, I'll give you a second clue. It's even more rare for politicians to then behave as if the result of a non-binding referendum is binding.
I could enumerate for you the remaining peculiarities, but if you're curious you'll find plenty for yourself.
I do understand that people often like to point to simple cases like this and say "That's Democracy!", inevitably those people don't have a great understanding of the meaning.
This referendum was more or less a confidence vote on the government. If British democracy were functioning properly, the government would have resigned, and the people would have had a chance to elect pro-brexit representatives.
But Britain adopted fixed election dates, copying the American electoral system. And referendums, for that matter, aren't very parliamentary.