Gambling is a form of entertainment. If you go to the beach during the holidays, travel to a country for tourism, or spend time with your family and watch TV, watch movies, talk, dance. All of these things are forms of entertainment too. So there is no problem with people gambling during the holidays, as long as they always play in moderation.
When I win, gambling is a big entertainment that will bring so much joy but when I lose, it is not entertainment because I just lost money so it is normal to feel bad. There is a popular adage in my locality that "money does not grow on trees" which means every money one gets is a product of efforts. I won't feel entertained losing such money unless perhaps I paid the money for comedy or shows specifically designed for entertainment.
In another perspective, if you gamble for entertainment, there is high chances that your emotion will mix up with your decision making which is not a good practice in gambling.