The defending alliance could not understand the intention of Sauron's side. What was the point of using the precious trebuchets to fill the land in such a critical time? Even if they could fill up the muddy area, so what? The City Wall was not breached. Minas Tirith did not enjoy its reputation as the most impregnable city on Middle Earth for no reason. Were the enemy going to climb the City Wall by piling up Orc carcasses too?
But the defending alliance was also well aware that the attacking alliance would never do anything pointless in the current period when every second was as valuable to them as gold. Therefore, despite not knowing the enemy's true intention, it did not stop the defending alliance from desperately bombarding the trebuchets below the city. However, because the attacking alliance was only targeting the area in front of the City Wall, their trebuchets had long retreated out of the range of the city trebuchets.
