Why does Faber call himself a coward?

Faber calls himself a coward because he realizede what was happening long before.... the censorship, the mind control, the ever decreasing lack of knowledge within society, and yet, he did nothing to stop it.

"Mr. Montag, you are looking at a coward. I saw the way things were going, a long time back. I said nothing. I'm one of the innocents who could have spoken up and out when no one would listen to the `guilty,' but I did not speak and thus became guilty myself. And when finally they set the structure to burn the books, using the, firemen, I grunted a few times and subsided, for there were no others grunting or yelling with me, by then. Now, it's too late."