Using hypo to mean hyper is indeed very confusing. In medical terms hypo is very commonly used in the "correct" way.
Some factoids: Simple carbohydrates or not matters little to GI. White bread is allmost up there with pure glucose; apparently long unbranched starches are very easy to break down quickly even though they aren't really "simple". Sugar has a much lower GI than white bread because of the fructose component(fructose takes a long time to convert into glucose. If you just hydrolyze sucrose you get equal parts sugar and fructose), but people tend to eat a lot more sugar from candy in one sitting than starch from bread.
The reason pasta is a very low GI food is 'mechanical', the starch grains are embedded in a 'matrix' of protein which makes it much slower to get at.