A couple of things there. Three, actually.
"All Scripture is God-breathed and is useful for teaching, rebuking, correcting and training in righteousness"-- 1 Timothy 3. This tells me a couple of things. First, it tells me what scripture is and what scripture is not. Scripture is a curriculum for learning righteousness. Not for archeology or astronomy or anthropology or even history, but for a specific ethical philosophy. In that regard, it should be taken to a great extent as "instructional fable" providing teaching material toward a philosophical goal. Second, it says "all scripture," which means not only each verse of scripture in particular but also all scripture as a whole.
What business is it of mine to judge those outside the church? Are you not to judge those inside? God will judge those on the outside; but as the Scriptures say, "You must remove the evil person from among you." -- 1 Corinthians 5
Among the things it teaches is that as a curriculum for a specific ethical philosophy, it really only applies to the followers of that specific ethical philosophy, and only the actions of those followers can be judged by whether they adhere to that particular philosophy. In other words, "club rules" only apply to members of the club.
You hypocrite, first take the plank out of your own eye, and then you will see clearly to remove the speck from your brother's eye. -- Matthew 7
How can you say to your brother, 'Brother, let me take the speck out of your eye,' when you yourself fail to see the plank in your own eye? You hypocrite, first take the plank out of your eye, and then you will see clearly to remove the speck from your brother's eye. -- Luke 6
Ultimately, the purpose is to remove the speck from my brother's eye, not to ignore it. That is, I am removing the speck. I'm not merely criticizing him for having a speck in his eye, I'm saying, "I will do that for you."
But first, I have to be clear of problems (at least that problem) myself. I have to acknowledge that I'm not just vulnerable to that problem but actually suffered from that problem myself. It's not "there but for the grace of God go I," but "I was there, and only by the grace of God am I not there now." You don't jest at wounds when you bear your own scars.
In order to become competent to remove my brother's speck, I have to experience removing my own log.