Some people see no harm in promoting a folk remedy that in fact has no effect.
Conclusion
There is harm in promoting a folk remedy that has no effect.
Evidence
People who are convinced to use an ineffective remedy continue with it for years rather than pursuing conventional treatments that would almost certainly help them.
Evaluate
We know that the rule we select needs to help us prove that "doing X is harmful" or some equivalent synonym.
Why is promoting folk remedies harmful?
It's not literally harmful, because the remedy has no effect, but it steers people away from treatments that would probably help.
So we're defining "harm" as "directed you away from something that would help".
Goal
Look for an answer saying something like,