Yeah, betting on your favorite team to lose could very well be a team fan's revenge for a bad game.
But in my opinion, this behavior is not worthy of a true fan and is akin to the behavior of spouses who separate after a divorce, who simply dream of creating trouble for their ex-husband. And they passionately wish that everything would be bad for their ex-husband and there would be more problems. In general, let's hope that among the real fans of different teams there are still very few such fans, one might say traitorous fans.
It is a fact that it can be like that, we as players, as bettors and as people who can make the difference sometimes our favorite team loses, but not because of that as revenge we should take such an action, no matter how much anger you have is not the way, by the way great example that you said, in itself I believe that no failure, no type of loss is pleasant, and when it is about money much less, no one likes any failure unless it is something masochistic, the rest what can be learned from a failure is lessons.