He doesn't have the power. Only an agency can ban a crypto or the Congress can pass legislation to ban it. The former possibility is not easy: the agency has to both have the authority and follow legally binding procedures. Several of Trump's executive orders have been struck down for the former. The census citizenship question failed did to the latter. "Contrived reasoning" is a failure to follow judicial procedure.
RE: Is it Possible Donald Trump Ban Bitcoin? - CoinDesk