easy. it works better to agitate anything when cleaning, not just clothes. Imagine washing your hands by just puting them in water and not rubing at all, some s…tuff would come off but if they are dirty most of the stuff will still be on your hands. with clothes it is even more necessary because the are porous and things can get stuck in the fabric, aggitation forces water through the clothes and moves new cleaner water to the area. Also the physical movement helps break up the molecules of whatever might be in your clothes which increases the surface area and allows for faster and more comlplete wash. There are more reasons, like to evenly spread the soap around which breaks up the dirt molecues and allows it to be washed away and not stick right back on the clothes. \n.
\nI suppose if the clothes were not very dirty and if they sat for a long time in soapy water, then were rinsed several more times than usual, agitation would not be necessary. so basically it works alot better to agitate the clothes while washing. ( Full Answer )