Earlier quoted context omitted.
Model as in model organism, like fruit flies in genetics, or mice in biology. Lacking a model organism means we can’t do much in the way of experiments and that means we learn much slower.
They said "we still don't have a fully functional human body model", as if one was pending or expected to be developed already.
Well, I think he/she explained rather well the reason why - and the extent to which - such a thing would be useful. That plus knowing the amount of effort expended in the rest of the field of medical research today ... it is indeed surprising that nobody has bothered to even try to produce a human body model. The feat probably wouldn't even require genetic engineering. (Then again, the amount of rote concepts in biology has steered me clear away from studying it beyond a single required high-school class, so what do I know.)
My best guess is that there must be some kind of fear, among that field's practitioners, that some stupid politicians (gah, redundancy!) would take one look at the project and throw a hissy fit or worse.