did evil in the sight of the Lord from all the abominations of the nations which the Lord had exterminated before the face of the children of Israel (2 Chronicles 33:2 LXX).Hezekiah had set an example of what to do and the Chronicler said that he did the "truth" (2 Chronicles 32:1). Manasseh set off in a new direction. Specifically he wanted to imitate the nations around him. He seems to have thought that if he just kept in the middle of the nations round about him neither excelling nor doing much worse, that he would be doing well. The Chronicler ends his discussion of Manasseh's reign by talking about
all his sins and his apostasies (2 Chronicles 33:19 LXX).The plural form of the word here is unusual since one usually sees the singular in Greek. The Hebrew has the singular and uses the term ma`al signaling treachery or covert betrayal.
So being like everyone else is, in the Chronicler's eyes, apostasy.