It's not a "programming language" function, it is all in how the particular CAD system in use at the agency is configured during the build stages. Some lower volume agencies may prefer object oriented unit boards. Most high volume agencies do not. Too much work when you're working a busy radio channel/talk group. Command line is the only way to fly.
My agency currently uses InterAct, which is pretty old, and most of it is designed for command line use. Our dispatchers are accustomed to this, it's easier to use CLI and enter "243 S/87 I-85S @ S FULTON PKWY" then to right click a mouse or click on a unit number on the unit board module, then open another window to enter the details of the call. The CLI will interpret the unit number, call type (in this case, a traffic stop) and parse the location, verify it against the GIS, and create an activity entry instantly.
We are in the process of rolling out Superion (formerly known as SunGuard/OSSI) and it too uses CLI to drive many modules. Not sure what language either system is written in. At the end of the day, the vendor is responsible for the coding, the agency is responsible for making sure the builds are created to the specification and that it functions how operations needs it to.
Every center is unique and has different needs.Every CAD/RMS product is different in how it behaves.