I'd be unimpressed with the business acumen of both the entrepreneur and the programmer. An entrepreneur who relates confidential information without an NDA has created difficulties at the very outset of his enterprise, which may or may not be costly later. (Consider the nonsense of the Facebook litigations.) A programmer who refuses work because he won't sign an agreement that merely binds him to refrain from doing something he would never want to do anyway, has refused work for no reason at all.
Of course, an overreaching and overbearing NDA is unsignable, and of course one with other provisions (noncompetes, etc.) raise different issues. But a routine NDA should be a non-problem for an honest programmer who doesn't intend to steal anything. And the failure to sign, at least for me, is a big red flag that another programmer would be a better solution.
Get over yourself. Most of us are fungible. No reason, other than inexperience, naiveté or reserving the right to cheat can be given to refuse, all of which make the programmer unsuitable for the task. As far as the moralistic argument about starting the relationship on the wrong foot, welcome to the twenty-first century, refusal to sign an NDA is precisely that, starting the relationship on the wrong foot -- it assures suspicion. And don't think refusal to sign puts you at a legal advantage, there are plenty of common-law and statutory ways to reach someone who has misappropriated, PARTICULARLY if it is explained to the judge that the refusal to sign was simply for some moralistic, idealistic handshakey kind of deal.
Tl;dr -> Refusing on that basis is a silly idea. Don't be silly.