Maybe I'm showing my age here...
The first time I went into a darkroom with a yellow safelight I thought there was something deeply wrong; I learned to print in 1970 at summer camp, and we had a single dark red bulb hanging from the ceiling for our safelight, even though we used graded paper only. When I took photography in high school four years later, we had a yellow safelight (I think it was an OC filter), and though the darkroom was much brighter and we were using Polycontrast paper, my muddy prints were somehow my fault, never related to safelight fogging (and at 14, I didn't know enough to even try to argue with the teacher).
When I get my darkroom darkened, it'll get LED safelights, if I can make them work from mains power, and they'll be red, red, red. To me, if it's not red, it ain't really a safelight (and no, I don't develop film by inspection).