Rashi: This is Tikun Soferim. He meant that via their silence, they condemned Hashem; the verse writes that they condemned Iyov. Similarly, "va'Yamiru Es Kevodam b'Savnis Shor" means Kevodo, and "v'Al Er'eh b'Ra'asi" means b'Ra'asecha. There are many cases like this in the great Mesores.

Ibn Ezra (here and 42:17): Yes. They said "Ra'asecha Rabah" (22:5), "Yarshi'acha Ficha v'Lo Ani" (15:6). Surely Hashem is justified, but it is possible that Iyov is a Tzadik! Hashem can afflict to punish for sin, to remove sin, or in order to increase reward!

Malbim: Yes. It was seen that Iyov is a Tzadik. They should not have contradicted this, and condemned him, because they had no answer. They should have searched for a way to make both true - Iyov's virtue, and that the afflictions properly came upon him.