Alex is not the only intelligent person in human civilization. On the contrary, compared with wisdom, many people in the head of state's think tank surpass Alex. When discussing how to deal with the retaliation of the solar civilization, it was not that no one had proposed plans similar to false comets, but these plans were excluded as early as the initial discussion stage, and they did not even have a chance to be presented to the head of state.
The reason is very simple, because there are several fatal loopholes in this plan, and it is precisely because of these loopholes that it is basically worthless.