charliehall: It is irrelevant in at present all laundry detergents are made with non-animal ingredients, since in the past they clearly were. Therefore many kosher consumers prefer products with a hecksher. And she this is a capitalist system, the manufacturers and kashruth agencies meet the consumer’s demand.
One can often rely on assuming a product uses the common ingredients and you will usually be right, but for many kosher consumers “usually” isn’t good enough, and they want “always”.
If you look around the “web” many people, not just us, are concerned about animal products in non-food items used for cleaning, since the traditional way soap and detergents were made involved animal fats.