We can't create an algorithm determining whether a computer program halts or not, but we can write one that checks whether it conforms to natural language specifications much more easily? That makes no sense. There's no exception to the halting problem regarding "human comprehensible" computer programs.
They're saying most useful programs don't fall in the complete / correct divide. You can get a lot done while restricting yourself to provable programs
Rice's theorem says that we can't draw a partition between two sets of programs, based on their semantic properties. It says nothing about drawing a partition slightly to one side of the desirable partition, misclassifying some tricksy cases, but correctly classifying all the programs we care about.