Yes -- this is what engineers who refuse about sales never come to understand. The decision is typically emotional; the facts are assembled and interpreted to justify the decision.

The reason it isn't insane for VCs to invest money into ambiguous situations even knowing that we are doing this is because the enterpreneur who can't get the a VC to be emotionally positive isn't going to be able to get anyone to be emotionally positive about what they are doing (recruits, customers, press, etc.). Conversely, the best entrepreneurs often marry great product skills with great sales skills.