Because thinking and speaking well form the basis of existence in a community, rhetoric prepares you for every occasion that requires words.That's quite a claim. (And some might expand the claim on the grounds that thinking and speaking need not involve only words.) Although I suppose 'prepares' and 'prepares completely' are not the same thing.
Fierce attention to clear and precise writing is the essential tool for you to foster independent judgment. That is rhetoric.I don't know what to make of this. I'm all for clear and precise writing, but what exactly is its connection with judgment, let alone independent judgment? Clear expression should help clear understanding, but can one write clearly and precisely about a subject one does not understand? And isn't the meaning of clarity and precision something that varies from subject to subject or context to context? Yet knowing that hardly tells one what to say or write, or how to say or write it. So it doesn't prepare you for every occasion that requires words.
I don't have much more to say about this except that the claim made here on behalf of rhetoric seems excessive. And it reminds me of some claims made on behalf of economics, e.g. that it is the science of behavior (wasn't psychology meant to be that?), so that if you know economics then you know what people will do in this or that situation. Is that a helpful connection to make? It seems like a bad sign when any subject claims, or is claimed, to have an application as broad as this. But is it necessarily? And where does that leave philosophy?