This is an important thing to consider. It used to annoy me that people would dismiss an idea or company because of some peripheral (and not necessarily material) bit of information. Jim Breyer was an investor in FreeGate (a startup I did in the first bubble) and he explained it fairly simply, he said "Chuck, people invest (or don't) for their own reasons, not all of them (either the people or the reasons!) are rational." And what that means for the budding entrepreneur is that you have to cater to the irrational ideas that live in the ecosystem, even though they are irrational. The whole "we won't invest if your seed round investor isn't" is similar to people who won't hire engineers if a company that they did an internship with didn't offer them a job. Irrational, but it's something to be aware of.
I think it's also due in large part to VCs giving you one reason when it's actually another. They want to leave their options open. Sometimes saying the real reason would leave you not wanting to work with them in the future. Giving you a trivial excuse that seems stupid is better than one that's offensive or makes them look like an asshole.
