"Why do you call our staff 'users?' They're actual people; they're our employees."
Well, yes; some of the people we're talking about are employees, but not all. And some of the people we support (computer users) aren't your employees.
When we IT people say "users" we're not talking about your employees. We're talking about people who interact with (use) your network, some of which might be your employees. And some of them use your network but aren't your employees.
If we say 'employees,' you might think that we're talking about your W-2 staff only, specifically excluding everyone else who has user accounts on your network, including contractors, interns, volunteers, etc.
But we're not; we're talking about the people who use your network, regardless of their employment status.
They're users of your network, or, you know, users 😀