Installing Arduino IDE on Linux
The problem here is that there are multiple flavours of linux each with their own installation and package management systems - Aptitude, Yum, EMerge, etc. 

It is not easy for Arduino to keep up with creating packages for each and every system, so instead they create a single tarball that can be used on any of the systems. 

At one point Arduino (or someone, anyway) used to create Debian packages for the IDE and upload them to the main Debian repository - however this has not been done for many years now and the packages in the Debian repositories are very much out of date (1.0.5 IIRC).

If you, as a system manager, choose to deploy the IDE system wide then it is your task to decide how best to do that.

One option is to just copy the contents of the archive to /usr/share/arduino and then run ./install.sh from within that directory.