The important part for the fuzzy understanding is shared context. This is what lets humans who have no languages in common communicate basic things in ad-hoc s

The important part for the fuzzy understanding is shared context. This is what lets humans who have no languages in common communicate basic things in ad-hoc sign language bits as well. And if the context fails, things can go just as badly as with computers, in the short run. In the longer run, people notice that something went wrong and are likely to go back to an earlier point and try to clarify, whereas computer systems are not great at it.