However, Google has stated very clearly for years that TOS violations will not be tolerated so I don't see that as Google pulling the rug out from under you.
Are you saying that the only reason any site has lost position under Penguin is for TOS violations? If so, can you tell us how you know this?
I didn't actually say, either, that they had pulled the rug from under me personally, although some of my pages have clearly been penalised for specific terms (which all appear related to backlink anchor-text neither posted nor solicited by me).
what part of Google's guidelines are lying to you?
It isn't just webmasters who are misled if some new agenda skews results away from being relevance-based. It is searchers, advertisers, and shareholders. It was relevance-based results that induced them to search through, advertise on and invest in Google.