Anything that runs you off unnecessary should be notified as being problematic, this days people tend to see gambling different because they earn a living out of it and they ignore the flags showing that they are possibly going through one or two problems. In that regards you don't have to lose a whooping sum in order to understand that gambling is a problem but rather you just need to see the signs.
If the sign is seen, then it should be prevented from turning into a big problem. It's when you don't pay attention to those signs that it will turn into a problem that will affect you. Just like you said, those who want to get financial gain from gambling will turn a blind eye to signs that are very visible stating that their involvement in gambling is affecting them
; they will rather want to look at those as an opportunity rather than a problem.