It is true, We couldn't compare gambling with other than trading and investment. Because in trading and investment these are permanent source of income, even these are risky but we could manege our lose in trading and investment. But in gambling, we couldn't manege it and gambling couldn't give us permanently money. Than as you said in gambling, it has a high lever risk than trading.
It is almost the same except for some parts. If people want to be rich from gambling then that is a wrong idea on why we should gamble. Sometimes people can win however Im sure alot of people lose so if you have other source of investment then just go for it, it is much better than using gambling as a source of making money