I'm not sure this means much. Several popular encryption schemes have been developed by or heavily influenced by the NSA (including algorithms mandated by FIPS

I'm not sure this means much. Several popular encryption schemes have been developed by or heavily influenced by the NSA (including algorithms mandated by FIPS and other government organizations), and there has been a lot of speculation that they added backdoors to AES and other algorithms. So in reality they've had the ability to add backdoors all along, and it's in their best interest to keep it a secret whether they've added one, so it makes complete sense that their chief would say this.