Well, I don't know that I believe that. I think he fired them for PR reasons. I'm not even sure they deserved to be fired. MLB did not choose to ban them or suspend them for more than one year, after all. Crane's position that they violated his franchise's values doesn't really ring true to me, just as nearly all teams happily tolerated and even encouraged PED use. The Red Sox are actually being more honest in a way, especially if they wind up not being found guilty of anything, but they also have a different GM than the one who hired Cora (and benefitted from the cheating, if they cheated). And the Mets essentially fired Beltran for lying in his job interview.
The feeling around baseball is the Astros weren't punished enough, so, barring suspending players, which was already off the table, and given you can't increase their fine, how else could they suffer? I do think not having a bench coach (as he would presumably be - and currently is - the manager) would be no small thing. And given the current state of their front office having an interim staff for one year would really hurt them in future years.
It's not that big a deal if a team has to be play with 24 guys instead of 25 when someone is suspended but it's still more punitive to the team than being able to replace him.
Like I said, it's not really enforceable. You can't make an owner not fire someone. But 2020 will definitely go better for the Astros with a new GM and manager than interim guys, if not as well as it might have with Luhnow and Hinch.