I think you understood this wrong:
this is the general NOC list, a list of all occupations within Canada. But they recently have changed this list, they have updated the list. Numbers are changed, professions are added and so on. This is very confusing for a lot of people, because, like in Immigration, they still use the 'old' numbers, but (some? all?) numbers changed. So that is why now, you can also consult the 'old' NOC 2006 list again.
This has nothing to do with the limited list of high in demand professions for Immigration (Federal Skilled Worker Visa).