I don't read this as being a defense of Stearns at all. It mentions his inactivity during the deadline, which frustrated many, including myself.
As for Yelich, injuries happen. It sucks for everyone involved but literally any player can get injured and derail a career at any moment. It's no one's fault, it's just a thing that happens and part of the risk of high dollar extensions or free agents.
Lorenzo Cain was far from a blunder. He was outstanding in 2018 and just fine in 2019 and 2021. It was only this year, the last of a long-term deal, where the wheels came off. And that's usually the case in any contract more than three years long, particularly to a guy in his 30s when the contract began. You're paying for the front end performance of those contracts and hedging against late-contract collapse. It's part of the cost of doing business in a sport with guaranteed contracts.