1)
Did [Yisrael] not heed Hashem even before Menasheh made them stray?
1.
Malbim: Yes. Because they did not heed the Torah, he was able to make them stray. Had they heeded it, they would have rebelled against him and not allowed him to put an idol in the Heichal. This was a sin of the Rabim, not just of the king. All are partners in the Mikdash!
2)
What is the meaning of "Min ha'Goyim"?
1.
Malbim: [They did evil] more than the nations [that Hashem destroyed in front of Bnei Yisrael].
