They may have no authority, but God's word will not return to him void. Is he suggesting people are wasting their time memorizing God's word? It might take hold, even if they might be doing it for a 'wrong reason'. Does he have authority? Prove it. The word of God has authority.
I am in no way implying that people are wasting time memorizing the Scripture. The point is that people will memorize to be able to quote it without actually living by the word of God. Specifically those knowing scripture without obeying the Word of God.
He is not saying there are people who memorize the Bible that don't have the anointing. He is saying there there are some who memorize is but are not saved. My pastor told me once and I don't remember his name but there is a non believer who knows the Bible in and out. It is his job to know it but he will admit he does not believe in it.