What does 2 Kings 23:13 mean?

He destroyed the high places east of Jerusalem, south of the Mount of Corruption, that Solomon, king of Israel, had built for Ashtoreth, Chemosh, and Milcom, the disgusting gods of the Sidonians, Moabites, and Ammonites. 2 Kings 23:13 - Modern Text Bible

(Josiah even goes after ancient sites of idol worship that had been around since Solomon’s time, showing how deep the reform goes.)