Is there enough lectin in green beans to hurt us bad?

No.: Only a small number of people experience GI distress or damage when they consume foods with lectins, and the amount you have to eat must be quite large OR the foods you eat not be cooked (or, in the case of dried beans, also rinsed) thoroughly. Green beans (string beans or haricots) have some lectins, but you'd have to eat an awful lot on a daily basis, raw or undercooked, to develop a problem.