What then? The people that do search for Pinterest will find it missing, and likely assume Google screwed up/their search engine is broken. They won't know Goog

What then? The people that do search for Pinterest will find it missing, and likely assume Google screwed up/their search engine is broken. They won't know Google banned the site or what for, they'll just think 'Pinterest should be coming up, it isn't, so Google is broken'. A problem that can be solved with a single line, “Pinterest results not included for x reasons” is no problem.