Luckily in the US, being very wrong about something, even when it's very consequential, is not illegal. We'd have a much less entrepreneurial society, and a lot less open, free debate, if it were.
Lucy Calkins did not force people to follow her methods, she persuaded them through teaching and advocacy.
FWIW I think a lot of affected students would have a reasonable civil case against Teacher's College, and other places where teachers were taught this nonsense, for harms done. If medical doctors were routinely taught something wrong and contrary to the published research at medical schools, we'd probably be thinking about a similar suit. But we don't generally put teachers and doctors in the same bucket; for one thing, teachers don't take a hippocratic oath.