100% white cotton, and even polyester or poly/cotton sheets should be labeled “Any Bleach When Needed.” Know that some textile manufacturers cut costs by putting the most restrictive care instructions on everything regardless of how best to wash it, so they only have to make one type of care label.
This isn’t fair to consumers, who rely on accurate information to know how best to care for a garment or textile. So go ahead and bleach your white cotton sheets and towels!