we didn't start the fire... so what?

Blame is spelled "B-lame."

It's an escape mechanism we use to get out of awkward situations we should stay in and work through, like using a parachute to get out of a plane because we're afraid someone will hold us accountable for taking one too many bags of free pretzels.

What feels like a way out of one situation only makes matters worse and forms new situations.

 
This is especially true if we never get caught, for if we get away with our choices now we'll assume that will always be the case. One day we will stand before God in a final judgment over our lives, and we can't in that moment point fingers to blame others for our own choices.

Then again, we didn't start the fire.
"The man said, The woman you put here with me‑‑she gave me some fruit from the tree, and I ate it. Then the LORD God said to the woman, What is this you have done? The woman said, The serpent deceived me, and I ate." (Gen 3:12-13) 

Then again, not starting the fire doesn't mean we should keep letting it burn everyone.
"So then, each of us will give an account of himself to God. Therefore let us stop passing judgment on one another. Instead, make up your mind not to put any stumbling block or obstacle in your brother's way." (Romans 14:12-13)