Not really surprising
""Traditionally we've thought that there is a small pot of individuals who are labelled as 'problem gamblers' and there's harm there, and for the vast majority of people there's no harm associated with gambling," Muggleton said. "But what we find here is that there's more of a continuum."
Look at pretty much any potentially harmful behaviour, and you see exactly the same thing. A small group of people who take things to clearly extremely detrimental extremes, and a huge pile of people who aren't quite so bad and span the whole range down to those who only indulge so rarely that any harm can't be measured at all. Drinking, smoking, eating, whatever, it's all the same. Why would gambling be any different?