They don’t say the word bad, but that is obviously what they mean. As John Wesley notes below, that is one of the three options, and the “Christian” Left has clearly dismissed the other two.
This book had to be written by one of three people: good men, bad men or God. It couldn’t have been written by good men because they said it was inspired by the revelation of God. Good men don’t lie and deceive. It couldn’t have been written by bad men because bad men would not write something that would condemn themselves. It leaves only one conclusion. It was given by divine inspiration of God. John Wesley
The Bible claims to speak for God in whole or in part several thousand times. So either the authors were correct or they were a bunch of blasphemous pathological liars. The text does not leave any middle ground.
The “Christian” Left does not believe that the Bible is from God, which is one of the reasons they are non-Christians.
1 Thessalonians 2:13 And we also thank God constantly for this, that when you received the word of God, which you heard from us, you accepted it not as the word of men but as what it really is, the word of God, which is at work in you believers.