I am not saying we should let diabetic babies die at birth. I am simply reflecting upon the fact that their genes would have been removed from circulation in the past; this is no longer the case.

If we disallow nature from taking its course, it will have consequences on "genetic quality". Following that train of thought and assuming we don't want to kill genetically malformed babies, an alternate route must be chosen. Better in-utero screening, CRISPR to fix the deformed genes, etc.