how to understand the quasi-cleft sentence "it is ...to which....who"?

Question

From "Qualified Homage to Thoreau" by Wallace Stegner:

It is Thoreau the moralizing enemy of the tradition to which he owes all his own authority who puts me off.

At first glance, it looks like a cleft sentence. But then I feel like there is something different, shouldn't it be "It is Thoreau who is the moralizing enemy of the tradition"?

On top of that, the two relative clause following just bewilders me: semantically, I don't understand "he owns all his own authority to the tradition; syntactically, I don't think the antecedent of relative pronoun "who" is "his own authority," though normally for restrictive relative clause the noun preceding the relative pronoun is antecedent.

Answer 1

The oddity here is that this sentence is saying that Thoreau is "the moralizing enemy" of a tradition, but it is that very same tradsition to which Thoreau owes his own authority. BillJ is correct that this is an "it-cleft" sentence. If we omit the supplementary phrase we have simply "It is Thoreau who puts me off." This is structurally clear, but fails to explain what it is about Thoreau that the writer objects to. The text could be re-written as:

When Thoreau speaks as the the moralizing enemy of the very same tradition from which he derives all his own authority, he puts me off.

This uses a different construction but has nearly the same meaning. It is, I think, easier to see the meaning, but this is wordier. Also the original implies that Thoreau always or almost always does this, while the rewritten version does not.