He's not arguing that Spielman is right. He's stating that he trusts him and others like him over less football centric folks that haven't played, coached or scouted professionally. It's the same way I think due to the smallest of things they know, that we don't.
As an example, I was a very good baseball player and was asked to walk on at IU. However, I was very untrained as an athlete due to poor coaching. These dudes knew so much more than me mentally and physically. I didn't stick.
Skip forward 30 years to me coaching my son in baseball. I thought I was doing alright until a former pro can't to work with me. I quickly made him the coach and learned directly from a pro. It was night and day. He still knows more than he can ever teach. After that we got another pro in the coaching tree and these dudes speak a different language that the rest of us can't keep up with. They are the real deal and they know we aren't.
So, here we are, only giving opinions and eye test analysis. I think I know OL and DL better than most on here, because that's what I used to be. But if I'm talking to a pro, I always acquiesce to their knowledge. Do they get things wrong? Absolutely. Do we get things right? Yes. But they get more right than we do by a long shot.