It's crucial to bet on sports you enjoy and understand. Without that, you might end up just chasing losses or making random guesses, which often leads to losing money.
There are many gamblers that are vast in sports betting and they bet on different kids of sports games and that's also how often they are devoted in watching, reading and learning about the events and fixtures of those games. Although you are right that making guess on sports that one doesn't have knowledge about could lead to lose of more funds but some player are betting on those sports by using other players prediction.