As a native speaker I want to point out that not having '
le' in there sounds broken.
I think the reason it's required is because you can have sentences without specific targets like this: "
Yo di mi anillo." "I gave my ring." This has a kind of "broad" flavor, in that not only does the meaning lack a specific target, there is also a suggestion of the target being an abstraction, as in something like "I gave my ring to charity." (This is the flavor I get from it). If you put a 'le' in there, it becomes "
Yo le di mi anillo." "I gave to him/her my ring." Which is a completely different meaning.
In your example, leaving out the 'le' starts the meaning off in a different direction than what the rest of the sentence does. So even in the case where it's redundant, you can think of 'le' as a kind of punctuation that keeps the meaning of the sentence from veering off into a targetless one before you've completed it.
So in this case it's not so much a matter of linguistic precision as it is a way of keeping the meaning consistent while the sentence is being read or spoken. That's my take on it anyway.