No kidding. A lot of "white" LEDs are actually UV LEDs with a phosphor. If you want to argue about it, try contacting this guy:
http://nortega.com/fastest-tool-to-clear-yellowed-thorium-lenses/
I bought one of these Jansjö lamps in Ikea Cardiff when I was visiting recently, they were selling the silver ones half price for £4.99, (yes I had the meatballs mashed potatoes and apple pie) I indeed used it to remove the yellow caste in my Canon FD35mm f2 lens and after about thirty hours exposure it worked like a charm and the yellow is completely gone now.