Slide 12 isn't a convincing argument that these people are okay, but of course it doesn't indicate the latter either. But even if these people are upper-middle-class professionals, there's still a chance that their action stem from things like depression/addiction. My hunch would be that the cause of the big spending leans more towards addiction than well-reasoned spending on a health hobby, but without data or evidence that's purely a guess.
It would also be interesting to look at the group of whales in general. Perhaps the very top 20 spenders are all well-balanced, healthy individuals with large incomes. But what about the rest of people who are spending large amounts of money? This might be where struggling individuals are more likely to be found.
I think in the absence of data, people see what they want to see such that it agrees with their worldview. Nobody likes to endure cognitive dissonance. Even in the presence of data people see what they want to see. Me? Well, some of the time the people spending money are sorely addicted; some of the time they have a mental illness like depression / mania / psychosis / schizophrenia / OCD / whatever; some of the time it's credit card fraud; some of the time it's kids spending their parents' money; some of the time it's just some person with access to a lot of cash that decides to throw money at the problem of becoming good at the game. It would be really neat to see some numbers.
It would also be interesting to look at the group of whales in general. Perhaps the very top 20 spenders are all well-balanced, healthy individuals with large incomes. But what about the rest of people who are spending large amounts of money? This might be where struggling individuals are more likely to be found.