Thanks for the link. It does say, under the web page "Common items that may be hazardous", that photographic supply "Could contain acids, corrosive materials, bleaches, or poisonous materials". Such a statement is so unclear that it may or may not apply to anything photographic. I guess if one ships a bottle of distilled water for photographic use it may be hazardous too. If it spills the shipper will be in big trouble if the bottle says photographic supply.
My guess (again just a guess) is since it is not specifically spelled out you can ship them as long as they do not spill. Once there is a spill the shipper will be 100% liable for the consequence. Only hazmat licensed shipper can ship (and spill) without liabilities.