Because Volquartsen will void the warranty if you do use one in their barrels.
I basically agree with you. I believe if you clean from the breech end and do it correctly with a clean 1-piece rod, jag and patch, you will never damage the barrel in any way. However, since .22LR ammo doesn't have jacketed bullets and since you will never damage a bore with a rod you don't use, there's no real reason to use a rod in a .22LR barrel. Besides, the pull-through "weed whacker" method of cleaning is much easier than pulling the action out of the stock, removing trigger group and bolt in order to use a rod anyway.