"the study is silent on these factors"
Well, if the data has been properly anonymized I do not fin dit surprising that socio-economic class is not in the analysis.
Gambling is certainly an activity tainted with reproach, but, just like tobacco, that doesn't keep every government from benefitting from it by allowing it and taxing it.
Of course, you cannot forbid gambling because, if you do, you'll just get criminal gambling centers run by thugs. So it makes sense that the government has a hand in ensuring that, at least, the gambling is done fairly.
You also have casinos, where gambling is authorized and, hopefully, the casinos are regularly audited.
But, just like prostitution, gambling is not going away.