A destructive choice is one that damages the player or the game in such a way that it can no longer continue normally.

For example, giving away all your money and getting nothing in return, or building yourself into a corner where there are no legal moves, or sabotaging the game in a way that causes it to end early.

Put in simpler terms, a player should not be able to make a choice too early on that makes the game effectively unwinnable or unplayable, either for themselves or for others.