I haven’t seen a lot of comments stating:

As a manager I explored existing pools to determine if I could backfill.

I posted an expression of interest to see if I could d’ufologies your request.

I advocated for you to the Senior Director to support your request.

I explored the option of hiring a casual.

I explored the option of hiring a student.

I explored the option of asking senior management for more salary dollars.

The majority of responses are as you indicate - managers offering an array of excuses for why it cannot be approved.

Why am I not seeing a variety of responses indicated what they attempted to do in order to support this non specialized employees request for a temporary (6-12 month request)?

Do the managers consider what experience she might learn on her acting and bring back to your unit to benefit you in 6-12 months.

I don’t think managers are evil. I will never assume malice when it can be explained by incompetence.

I think a lot of managers get promoted into these roles because they’re good at their job. You’re a good administrator, eventually you end up promoted to office manager. You have a lot of office administrator experience but no experience as a leader. The government does not provide training to bridge that gap. A lot of managers end up over their head in these jobs and refuse requests because they don’t know the answer, don’t know how to develop other options, it’s inconvenient for them or they’re too busy/lazy to do their own research.