Why do we need a safelight in the darkroom?
We use a darkroom to safely handle light sensitive materials. We remove some pieces from them from their packaging and replace some pieces. We are mainly talking about photographic films and papers. However we could be talking about X-ray films, movie film, astronomical films and plates, etc.
Photo materials are naturally only sensitive to violet and blue light. If true, they can be handled safely in rooms illuminated by light that is missing these colors. We are talking, red, yellow, and amber. If you were to spend time in a darkroom, you would appreciate some limited illumination. It's easy to trip and fall and otherwise make mistakes in total darkness.
Now modern photo materials are usually treated to extend their sensitivity into the green and red regions of the spectrum. Now we must alter the safelights that we use so that they least effect these materials.
For some, its a dim green, useless except to keep you somewhat safe from stumbling. Sometimes nothing will work but total darkness. Sometimes we can us infrared light and specials vision scope.
As one who has spent years in the darkroom, I appreciate this stuff. If you worked the darkroom, you too would appreciate the safelight.