That is true Mo. There are also some people on here who boil their brushes to no harmful results even though most people around here recommend they don't. I think its more of a YMMV kind of thing and that it might or might not ruin the taste of food. With that being said, it is not recommended that you use soap when cleaning cast iron, and by no means am I proclaiming to be the expert I am just going based on what I have been taught and discussed with vendors of cast iron.
Yeah, I guess for someone who is just starting out with the cast iron, it is probably better not to. Just wipe, if possible, a little hot water or some salt if needed.
-Mo