I agree that sendmail (even the rewritten sendmail 9) has an apparently warranted reputation for insecurity. The weird thing is why someone wrote an app that calls qmail directly. The sendmail command seems to be the de facto standard API for sending mail, because the other mails can and do emulate it. So the Right Way appears to be to call ns_sendmail and let it call sendmail and let your MTA of choice simulate sendmail. And if I understand correctly, that's the decision the community has made?
Personally, I find that the djb tools exemplify unix: powerful, stable, and user-hostile. Or rather, administrator-hostile. They tend to fail silently and without explanation, which may (maybe?) be appropriate in some circumstances but makes them brutally unforgiving of mistakes or even just faulty assumptions while installing.
