Why are they called "Atzabeihem"?
Otzar Midrashim (Hallel p.132): It is an expression of sadness - "v'Atah Al Te'atzvu", "Harbeh Arbeh Itzevonech" (Bereishis 45:5, 3:16). Radak - they are sadness to those who trust in them, for they are not saved via them.
Malbim: They are not in Shamayim. They are close to [the Goyim], and they see their Etzev (image), but still, they do not help.
Why does it say that they are Ma'asei Yedei Adam?
Radak: How can they save man? Man made them!
Malbim: The verses teach their lowliness due to their substance, form, manufacturer and purpose. Their substance is silver and gold, which is inferior to wood, which has a vegetative Nefesh. Their manufacturer is human. Also refer to 115:5:1:2.
