The game is "hidden" from the public store, meaning you cannot find it by searching "Angry Birds Seasons" in the Play Store search bar.
While the official listing is gone, the game files still exist. There are two primary ways to play the game on Android today: angry birds seasons google play store free
In an era of hyper-complex battle royales and gacha games, why go back to Angry Birds ? The game is "hidden" from the public store,