It's not NIH at all. Electronic voting has not been implemented sufficiently. It could be done. It's not about doing it better, it's about doing it at all. It's not-invented-anywhere hubris, and that's plenty of reason to do something.
People aren't much harder to manipulate than machines, and they're also just as transparent. There is no fundamental reason to believe computers can't be more secure than humans when it comes to collecting data and tallying it.