@LXuser those tools were installed when you installed the “Keysight Fixed Licensing” Plugin (in your case directly, but they are also installed by the Keysight PathWave Test Automation installer).
The reason they are not uninstalled by default is that they can be dependencies for other Keysight apps. Basically, whichever Keysight application is installed first will install these and then they will be used by any others.
Do get them off your system you will have to run the uninstallers individually.
The rest of the OpenTAP directory is left around in case you are actually doing an update so nothing custom is uninstalled unintentionally. To fully clean up, you can simply delete the directory.