Why Brexit Sucks

Imagine a team of mountaineers having voted for a particular route up a mountain and this vote relied on the democratic principle of majority. Imagine half way up the mountain conditions became difficult and dangerous. Imagine that some of the team members opted for reconsidering their first vote, pointing out that lives might be at risk when just following the first vote. Imagine one team member argued that a new vote would violate the first vote and would thus undermine and destroy the principles of democracy. The mind boggles: why is a second vote based on new insights less democratic than the first one?