I'd say that most students running Linux opt to install their own development environment so installing the VM for them really isn't an issue. Either way, it's much easier for the professor to spend a class showing people how to install VirtualBox, and then the class VM than showing them how to install an entire development environment locally.
Here's how it works: the professor prepares an Ubuntu VM with the entire development environment set up inside it, and then just provides the image link for the VM. The students can easily install VirtualBox, and then all they have to do is download the image and run off that.
Here's how it works: the professor prepares an Ubuntu VM with the entire development environment set up inside it, and then just provides the image link for the VM. The students can easily install VirtualBox, and then all they have to do is download the image and run off that.