>Some years ago, in an American diner, I noticed US govt health warnings on the sachets of saccharin too.

And I think it took some lobbying to keep them there. Saccharin developed cancer in some mice which were overdosed with it by injection, so there's no conclusive proof that it can't do some of it to humans - but then there isn't any proof whatsoever that it can. So while this saccharin thing is actually undecided, saccharin is still labeled. OTOH, aspartame has a huge portfolio of findings against it, but there's zero warning on any of the products which contain it.

I'd say "go figure", but that's unnecessary. Lobby.