But the important thing here is that a game needs several things to be a functional game. Among those is player intentionality (that is, you can plan what you're doing and make a decision about play and impose your intentions onto the game state in some way).
Now, in Candyland as a game itself, you don't have any choices per se. You draw a card from a random deck, move that far, and let the other player take a turn. You can't take two cards or no cards. You can't take some penalty to draw the better of two cards. You have no game-level choices. So is this a proper game at all?
This is because you're an adult. When an adult sits down to play a game, they're already committed to play (generally). For the children the game is directed at, the actual decision making and intentionality lies at a meta level: do I sit and follow the rules, or leave the table to play with something else, or whine until my parents cheat in my favor? This is actually a meaningful choices that a child has to make. The actual decision making in Candyland occurs on the same level as the decision making in slot machine play: the real choice is whether or not to play. (Insert Wargames joke here.) Once that choice is made, it's all random.
Ideally, Candyland rewards the sitting at the table, following the rules, at least until the child is ready for a game with actual in-game decisions. But if the adults play their part poorly (and make no mistake: your role as adult is markedly different from the child's, even if this is never spelled out in the rules), then the child may learn that they can leave the game whenever they start to lose, or that Mommy will let her cheat to make sure Baby doesn't lose and start crying. Once again, there are meaningful choices for you the adult player, but they exist on a different level of abstraction than the colored squares and race game.