If you ask me personally, then no, we don't need to have such a vote. But if the point is that country wide referendums should only be held for important quest

If you ask me personally, then no, we don't need to have such a vote. But if the point is that country wide referendums should only be held for important questions but then exclude Brexit because "it's stupid" then that's an inconsistent argument. Surely the question whether the UK should leave the EU was a very important decision to make. That the vote went a certain way which you don't like does not make it less important of a decision. Unless the actual point is "referendums should only be held for questions that are important and will go the way I like". You can have that opinion but then please be honest about it instead of disguising it with supposedly neutral musings about democracy. (Hint: Democracy does not mean that only what you want will happen.)