Earlier quoted context omitted.
I don't think it's just presentations or even corporate culture in general. I sell second-hand goods online, and have found that explicitly describing any defect completely torpedoes the sales process. Having a photograph that shows it off clearly but saying nothing doesn't have that effect, though.
It’s the same bias, we’re so accustomed to sales pitches proclaiming perfection that an honest pitch sounds like the top of a disaster.
In reality, that is probably the case, but it's also the case that any culture always moves in this direction; the nash equilibrium is reached only if you describe your product a bit too rosy.