What edge do they have over the market to justify such evaluation
VC is a hits business. Just one hit pays for 9 that didn't work out.
The difference in hit rate matters enormously and the existence of a hit tells you nothing about the denominator.
The size of the bet matters too - you could wipe out a hit with one bad pick if that bad pick is big enough!
If you don't have an estimate of the rate that you trust, you're just throwing money at dreams.
But it's WAY harder to get rich by being a pessimist than by being an optimist. And if you're a VC choosing where to invest primarily-other people's money, then you have no particular reason to try to talk them out of the hype.