1)
What is "uv'Fachazusam"?
1.
Rashi: It is an expression of bewilderment.
2.
Radak: Amidst their frivolity. This is like "Anashim Rekim u'Fochazim" (Shoftim 9:4).
2)
Why does it say "I did not send them and I did not command them"?
1.
Malbim: Do not say that I commanded them, just I did not send them to tell the nation. I did not speak to them at all!
3)
Why does it add "v'Ho'il Lo Yo'ilu"?
1.
Malbim: They do not try to say something that will help. Just the contrary, they veer them from Hashem's way!