It's so entertaining when he loses and starts screaming and go 100% mental.

This is indeed quite funny to watch, but one must not forget that he is not serious. It's a kind of marketing, people now watch his videos and streams precisely because he's so upset about losses and people just tend to be gleeful.
So it's also a win-win for everyone: his viewers are happy to be entertained, and he's happy to get high click impressions and the resulting advertising revenue.