Apart from winning or losing, I believe some people bet on sports matches because they have a genuine love for the sport or support a favorite club. As a fan of the English Premier League, it's incredibly exciting to watch the matches every week. Meanwhile, the bets I place add an extra layer of enjoyment to the experience.
It is true that some gamblers bet during the game of a team they loved the most. There are some gamblers who bet on their team even if their favorite team is relatively weak and also some gamblers not only bet on their games but also bet to enjoy the game of their favorite team. Some of the gamblers only bet on selected matches after analyzing various types of data. Gamblers continue to support their favorite team despite knowing that winning or losing in gambling depends entirely on luck.
Winning or losing doesn't depend entirely on luck when it comes to sports betting, it is something that is applicable only to gambling games where nothing else can make you win or lose despite your luck, but in sports betting, your knowledge and experience and your research and analyzing skills play a great role towards your wins and losses. If you lack all these things, you will find it difficult to get much success in sports betting.
So the gamblers who bet on their favorite teams only to show support mainly do it because of the emotional connection they have with the team and not because they are trying their luck with the bet, if they do proper analysis, they won't bet on their favorite team since they would know it's weaker than the opponent.