You are presupposing that the elected official has a more realistic sense of the practical implications of policy than the seasoned bureaucrat who is a subject matter expert. It is in the public interest for the bureaucrat to provide “fearless advice”, and for the elected official to listen to it thoughtfully. That doesn’t mean they have to heed it, since plenty of “experts” can be too all easily rooted in the past.
But if I may reveal my own biases for the moment, I often see elected officials charging in like the proverbial bull in a china shop, with all sorts of ideas and policies that seem great on paper, and are eminently laudable goals that most would share, but with little realistic sense of how things actually work. Sometimes the intended policies can actually work against the stated goals, because the details (which the bureaucrat may have much greater familiarity with) have not been fleshed out.
The irony is that the bureaucrat might do a fabulous job of serving the objectives of the elected official, by being more knowledgeable about the realities and details, but the official does an end-run around them because they mistake the attention to problematic details as an objection to the goals.