1)
Why was he Metamei the Bamos, and destroyed the Asheros and Matzevos?
1.
Malbim: The latter were for idolatry, and were forbidden to [use for] Hashem. He broke and ground them up; it did not suffices to be Metamei them.
2)
What are the bones of man?
1.
Radak: They are the bones of the idolaters. He removed them from their graves and put them in the place of the Asheros and Matzevos, for disgrace, and burned them there.
