Neither his school teachers nor his university professors taught him the most essential things he came to value - a soaring sense of wonder, an evolutionary perspective and an understanding about mistaken ideas that everybody had once believed. Everything hinges on the matter of evidence. On so important a question as UFOs, the evidence must be airtight. The more we want it to be true, the more careful we have to be. No witness's say-so is good enough.
People make mistakes.
People play practical jokes. People stretch the truth for money, attention or fame. People occasionally misunderstand what they're seeing. People sometimes even see things that aren't there. The whole idea of a democratic application of skepticism is that everyone should have the essential tools to effectively and constructively evaluate claims to knowledge.