This is correct. It is bleached - - NoT dyed. I make my living (such as it is) in textiles.
Think undies....they are white when you take them out of the package. After a time the color starts to dull / change. That is because every time you wash them, the bleach is being washed away - little by little. As stated here in ECF, boil your wicking material very well. I would never purchase a colored wicking material because it contains dye. It is very difficult, if not impossible, to boil away the dye. They make dye lifters, but those are a bleaching material.
Bleach is found in most drinking water and is considered safe when consumed in small amounts. The amount of bleach consumed on a wick, after is has been boiled, would be minimal. That is why I use cotton for my wicking material. Hope this helps a little.
PS - the bright white, which almost hurts your eyes to look at it, most likely contains bluing. And bluing is a blue dye. If you get something that has been treated with bluing don't panic. Boil it well and it should remove 99.9999% of the bluing. Bluing contains a diluted / weak blue dye which has minimal retention and is mainly used for 'show', as in "See how White this is!" Boil it
