Tell me more about the VM, why we need it, how it realates to VM Ware or other ooen source VM projects.
Well, you have to practice and so you need a Database.
You can download the installers for your platform, , verify that your PC or Server or whatever computer you are planning to use complies with all requirements for installing an Oracle 12c database and then do the installation (pretty much what every DBA does). Then you have to create a database (also a DBA task).
Or you can just download a file and open it with Virtual Box and all that stuff is already done .
VirtualBox (https://www.virtualbox.org/ ) has no relationship with VM Ware, it is another virtualization software, that was developed by Innotek, then bought by Sun Microsystems and when Oracle bought Sun in 2010 was part of the deal, so now it is part of Oracle offering:
No other MOOCS have had that sort of requirement, so why is this MOOC different from all other MOOCS in that way?
Previous PL/SQL MOOCs also offered the "Developer Day" virtual machine (used on hands-on labs in Oracle events like Oracle Code or former OTN Tour) as a simple and free way to have an Oracle environment up and running:
Please read the course FAQ page to get details on other alternatives, like using Oracle Live SQL, Oracle's free cloud database (https://livesql.oracle.com/) instead of installing a the Virtualbox VM, or doing your own installation.