That guy is wrong about just about everything.
On Windows, you can get a piece of software called Process Viewer (
www.sysinternals.net) which is like a Task Manager to the Extreme. It lets you see the open files and folders.
On Linux, you can delete a file that's in use as long as you own it. Or if you're root, you can delete any file. You can use lsof (list open files) to find out who's using it.
The only real difference here is that Linux has the software to check who's using the file open by default.
And on a good Distro (like Slackware), you rarely have to install libraries.