The term calico has different meanings, depending on where you are, but in the US it is usually a low thread count fabric with a repeating print. Homespun fabrics are also a low thread count, loosely woven. The threads are dyed before the weave, so they usually have a checked appearance. I don't understand why Hobby Lobby calls their homespun calico - perhaps just a sign that the definition of calico is so fuzzy? At any rate, their fabric should do fine for rag quilts. I'm not sure what you mean by a regular quilting calico. The calico on the wall at JoAnn's is not a good quality quilting cotton, such as you would find at your LQS, but it is calico, and it can be used for quilting, but it would not rag all that well for rag quilts.