I agree, when consensus is the per-transaction kind used in, say, Bitcoin.

However, a Zero-Knowledge Proof-based consensus (https://zkproof.org) can produce agreement on a combined result without revealing the individual inputs.

It's not easy, and you still have to prove the protocol has been followed, that is that everyone voted even though you don't know what they voted for.

But it's a type of consensus which you do want.