The basic form of Monopoly starts the players with cash and no property. They take it in turns to make random moves around a cyclic track. After each move they can make choices to buy property, sell property or modify property. Players are eliminated when they have no more property or cash, and eventually all wealth and property is controlled by a single player.
I'm going to abstract this by one step, removing some of the ostensible symbols along the way.
The movement of the players is cyclical and random. Control of when and how the players can move is not controlled by the players at all. Each player must move, there is no alternative. Furthermore, each player must move a distance that they do not determine. Imagine these same two conditions in something like a dimly-lit house or hedge maze and we begin to see the basis of the horror situation. Furthermore, in this game form there is no exit from the house or maze, and the player will encounter the same room or feature over and over again. The players must move when they are told, where they are told, and to the same locations over and over again.
Accumulation is a necessary phenomenon, forced by both the cyclical movement and the survival instinct. Failure to accumulate guarantees the destruction of that player. Embracing the phenomenon generates faster accumulation. But the accumulation comes at a price: the destruction of the other players. Accumulation is the means for the survival of the self as well as destruction of the other. Ultimately, the monopolising player accumulates enough power to become the final agent of destruction who - in a final act of empty horror - rules over all the possessions in a city inhabited by a trail of corpses.
So I return to my original point: Monopoly is a horror game. Players move against their will to places they didn't choose and which they will revisit repeatedly. They do this in order to become the means by which all other players will be destroyed, leaving only a concrete cemetery to rule.
It all seems pretty bleak at this point, but there's a little ray of hope hiding in the rules, a way to avoid destroying or being destroyed.
No one buys anything.
Continue the movement around the board and accumulate the cash, but don't exchange it for anything in the game. Pay the occasional fine from Community Chest or Chance as you must, but it won't ever be enough to drain all your cash. The way out of the horror of Monopoly is a cooperative effort not to buy anything in order that everyone survives.
I've no idea whether this was the intent of Monopoly (probably wasn't) but I think we can draw a parallel for the moral choice to compete or cooperate. The former leads to lonely desolation and the latter leads to community survival.
Even the worst games make moral statements, often unintended.