Earlier quoted context omitted.
This list will impede velocity by quite a lot, especially with coming up with and implementing Plan B's
You only implement the Plan B if Plan A fails. Plan B doesn’t have to be elaborate. It can be as simple as, “I’m going to look into using this third-party service to solve 99% of this problem, but if it isn’t a good fit or it’s too expensive, I think we can put together a home-grown 80% solution in a couple of sprints.”
So that's not what they're advocating. Though I think they're 100% wrong on that point, and most managers would probably think so too.