I agree with everything you wrote above, which is an excellent argument against deleting the article Blood libel. But to my knowledge no one is suggesting that we do that. But the idea of removing the summary paragraph on blood libel and using a link in the see also section instead is a different issue, and I do not see how your reasoning above applies. The underlying issue is that unlike the other subsections in the article, blood libel really has very little to do with blood and a lot more to do with antisemitism.