Fly by wire and center of gravity?

Patrick answered another question in this way-". . .Fly-by-wire systems are very sophisticated setups that involve moving the CG so far aft that the plane cannot readily be controlled well by anything but a computer, and are rarely seen outside penger jumbo jets and military aircraft. . ." This got me thinking. In his answer he states that FBW systems involve moving the CG so far aft that only a computer can control the AC. Now I understood that fly by wire was created to control AC that were inherently unstable such as tailless and say radical delta wing designs and certainly the newest and greatest with thrust vectoring and all those bells and whistles. But I don't remember the reason being an intended CG relocation. Just an interested bystander. Only as (un)knowledgeable as the question and definition state and ask. Thanks