I'm a resource

I love it when project managers refer to human beings as "resources". It would be okay if they were using it in the general, but you never hear them talking about equipment as a resource. When they say "we moved three resources in place" they're not talking about three servers or trucks or manufacturing lines. They mean three people.

What is it about project managers that they can't just use a straightforward term that everyone understands? Could it be that they're hiding something?