“King Ahaz cut off the frames of the stands. He removed the laver from them. He removed the sea from off the bronze oxen that were under it. He put it on a pediment of stone. The covered portal for use on the Sabbath that had been built inside the palace, and the outer entrance for the king, he removed from the house of Yahweh. He did this because of the king of Assyria.”
After all the energy and time that had been spent in building the temple with all its ornamentation during the time of King Solomon, as described in 1 Kings, chapter 7, King Ahaz wanted these things removed, especially the bronze sea work. He did all this because he wanted to please the king of Assyria. It is not clear from the text how this pleased him.