It was a nonbinding referendum. I think it’s perfectly reasonable to ask why important policy decisions are being made by a simple majority of the voting public.
Didn’t the conservative party win a general election in 2015 in which the referendum was a manifesto pledge? So the conservatives promised a referendum and won that election - that seems like “the consent of the governed”, doesn’t it? And the british public could have voted for labour in 2017 or 2019 if they wanted a softer stance on Brexit, but they didn’t, and the Conservatives won both those elections too, albeit with a minority government from the 2017 election. Maybe that means something, in terms of what the british electorate thinks?
Perhaps, but landslide wins in U.K. general elections often involve significantly less than half the electorate voting for the winning party, and general elections come with all the baggage of the party manifestos and Red/Blue/etc. tribalism.
OTOH, there was a referendum on changing the voting system (which was also rejected).