Quora seems to only whiteout searches that land on an answer page. When I search for a user's name in incognito, I can see their whole answer history unobscured.
You can disallow search engine indexing from your settings under Settings -> Account -> Allow Indexing (disallow) if you're worried about it.
When I click the "answers" tab on the sidebar of a user profile, I can see the entire user's answer history unobscured. Is this not the case for you? Maybe we're caught on different sides of an A/B test, although I keep getting the same results in new incognito windows.
You can disallow search engine indexing from your settings under Settings -> Account -> Allow Indexing (disallow) if you're worried about it.