Good, level-headed post. You listened to the interview. My comment about preparation came before I listened to the interview. After I listened, it was just as you described it.
However, I do think penalties is a matter of coaching. I say this because it seemed as if Jimmy Johnson's teams (and Belichick's) were among the least penalized and less turnover prone. How does that happen? Why is it that one team is more prone to penalties than others? That is a factor of teaching and practice.
Unfortunately, we don't have the opportunity to know how or how much teams practice staying on-sides so we don't know exactly how penalties are being addressed at practice. But we make too many penalties. It's not just dumb players. And if it is, maybe those dumb players don't need to be playing. That's an issue of coaching too, i.e., if you're letting players who are consistently making mistakes stay in the line up.
That's why Dee Ford is no longer a Kansas City. Stay on-sides and the Chiefs are looking at playing in their fourth straight Super Bowl.