On this forumn you will get many opinions from people who stay all over Adelaide. Sometimes they are an informed opinion from real people who live in the areas that you ask about and at other times they are an opinion from people in distant suburbs who type to get a response.
When you are half a world away it's sometimes difficult to sort out what's fact and what's not. I wouldn't know whether Colonnades is the worst shopping centre for low class people in Adelaide as we have some very mixed socio economic suburbs throughout the city. Maybe just when I shop there in my trackies and thongs!