The OP asked about the legality of Homeopathy. If that's the question, we should consult the law.
"Subpart F--Specific Requirements for Descriptive Claims That Are Neither Nutrient Content Claims nor Health Claims"
I have never seen any homeopathic products. To they contain the FDA disclaimer?
"These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease."