to me gambling is only fun if you are winning money in gambling, but if you are not making money and continuously loosing it then you are really mot getting fun from gambling.
But then you are not playing to have fun you are playing to get profits for the people that actually play for fun the outcome is not important they are there to make friends, meet interesting people, to relax, etc.
South park is right that is why gambling is very fun because you are going to get a lot of friends who are addicted gamblers too. So I would say that gambling is fun because of many reasons and all you have said are right. But for me, the main reason why it is very fun is people are able to get some profits if they are going to be lucky with me.