On PCs IE/Edge [Safari on MAC] is needed to power the Ruby 'web-dialogs' which are still used by many extensions, including SketchUcation's.
It does not matter what your day to day web-browser is set to be, as this is is never used...
Windows has always installed a minimal IE set up to support legacy products like this...
Web-dialogs are now 'deprecated' but they still work just fine.
A newer 'html-dialog' is available through the SketchUp Ruby API [which uses a now built-in Chrome browser in SketchUp].
Unfortunately it is not a simple matter of swapping a few lines of code over in the various Ruby files !
It requires considerable reworking in both the Ruby files installed on your PC, and the html/js files with which it interacts 'server-side' - some of the callbacks and other basic functions etc have been changed considerably.
A change over is planned by us, but we are currently engaged on other more pressing changes at SketchUcation, and so I can't give you any clear indication of the timescale...
Meanwhile I suggest that you get IT to reinstate a minimal IE installation on your systems, as their action has been somewhat presumptuous and unnecessarily limiting.