> If this is true then those shouldn't even be public job postings.

Why? Not everyone is on LinkedIn or has an updated profile.

Some of the best candidates I've hired were people who were in other states who were planning to move, but waiting for the right job opportunity to come up.

We also used recruiters.

Why does it make people so angry that we posted job listings for real jobs that we were really hiring for?

If your real candidate pool is so small that you're effectively targeting a handful of people worldwide then you aren't "really hiring"