I think it more interesting why some people want to believe such nonsense. The price of fish is all the evidence you need. Glass half empty does not begin to describe such a mind set.
Fishing techniques have improved rapidly over the past few decades. The price of fish is only a measure of supply in as much as we can continue extracting fish. It's no indication of how close we are to running out.
The mindset that it is worth keeping an open mind if the consequences are potentially catastrophic - is that the mindset you are having difficulty with?
