Skenes is a money maker, which is far more valuable than maybe winning more in the future for the Pirates owner.
They're not trading him until he's got a year left.
The only reason Betts was in his walk season was because the Red Sox decided to play broke. The Dodgers signed up to an extension before entering FA. So from the perspective of Red Sox fans they aren't looking at it as a walk year trade.
It's not about not trusting your starter in the first. It's about not trusting him to face the top of the lineup a third time through. You use the opener so he can face the bottom of the lineup a third time through, and not the top.
More than just the PR, he's also a locker room cancer. And he's not a CY Young level pitcher anymore, his talent is nowhere near enough to justify the headache.