They sound like a supervisor I once had. OK, several of them over the years. Asking to pluck support for their position from thin air because they had already promised someone that a course of action would work, often ahead of schedule and always far below budget.
It usually involved the phrase, "Can you prove it won't work?" I would say, "Yes, let's do a test." This was met with "This isn't a science project. We're not funded so you can amuse yourself."
Needless to say, I don't work with people like that.
It's too bad that ethics isn't a marketable skill.