Once this idea was proposed, it immediately convinced the council, because no one could guarantee whether the enemy had mastered the technology to reach the solar system. As they had previously portrayed the enemy as strong and cunning, this possibility must be taken into account, otherwise it would be contradictory. Obviously, the safety of the solar system was of utmost importance, being the objective of the expedition. Precaution is always better than cure; it's better to eradicate the enemy at its inception.
Furthermore, the solar system also entered a state of war readiness. However, it wasn't yet open to the public to avoid any unnecessary panic. The other fleets in the solar system had already started their training, ostensibly to fight against the Interstellar Pirates and smuggling.