This is conspiracism-adjacent, IMO. Plenty of consequential decisions have been put to referendums, if only because the political class may not want to take responsibility for them. And the outcome of a referendum is never certain.

The more interesting difference is surely in how the elite responds to unexpected referendum results. Plenty of mainland Europeans assumed that Brexit would somehow be canceled (which was surely the right thing to do on paper). That was never going to happen. British political culture sacralizes majorities. Canceling a referendum "victory" is as anathema as proportional representation, coalition government, or limits on parliamentary sovereignty. This (IMO archaic) understanding of democracy partly explains the Brexit result itself.