While luck is a factor (of course), the substantial effort and skill involved make sports betting distinct from typical passive income. Therefore, I believe that sports betting winnings should be classified as active income, similar to trading or commerce, which involve both risks and the potential for profit or loss, like in any business.
After all, winning is not guaranteed in gambling, unlike in typical business. You can't, and certainly not OP, think gambling will be considered passive income or even another source of income. Although sports betting does not rely fully on luck, we can still rely on our future for unreliable sources.
Indeed, you are right about mentioning the risk, but gambling is a riskier game than any other form of investment. It is far from running a business, as if you can manage it well, profit is possible, and you can consider it passive income. Unlike gambling, where you can't ensure that you will win every day.
The difference is that if you become addicted to gambling, you will never win anymore but just lose. But if you get addicted to business, you will be earning more.