-> "A good developer would never put the end of the digestive system right next to the start of the reproduction system - not even if that would require fewer lines of code (which it undoubtedly did)." Whatever point he's trying to make in this post - and I'm not going to take the time to try to figure it out - I'm sure there's a simpler way of saying it.
Basically, "biological" describes a system that works decently, and which has grown through incremental changes, and yet is a poorly architected mess inside. It describes something that appears to be great from the way it works and the way it looks on the outside, even if the internals are a mess that require 10 years of schooling and residency to fully understand and maintain ;)
Not even that! 10 years and continual refresher courses and on-the-job training for a lifetime -- just to have an inkling and at best a hazy but uncanny knack for fixing. But even this is not even enough in all cases.