So you believe that you know others well enough to be able to evaluate if they are Christ's based on their sin? How many people show their sin or even admit it? Sin is kept very closely guarded.
What we are told is not to evaluate others by their sin, but by their fruit.
Matthew 12:33
"Either make the tree good and its fruit good, or make the tree bad and its fruit bad; for the tree is known by its fruit.
Luke 8:14-15
"The seed which fell among the thorns, these are the ones who have heard, and as they go on their way they are choked with worries and riches and pleasures of this life, and bring no fruit to maturity. "But the seed in the good soil, these are the ones who have heard the word in an honest and good heart, and hold it fast, and bear fruit with perseverance.
John 15:1-8
"I am the true vine, and My Father is the vinedresser. "Every branch in Me that does not bear fruit, He takes away; and every branch that bears fruit, He prunes it so that it may bear more fruit. "You are already clean because of the word which I have spoken to you.
Galatians 5:22-26
But the fruit of the Spirit is love, joy, peace, patience, kindness, goodness, faithfulness, gentleness, self-control; against such things there is no law. Now those who belong to Christ Jesus have crucified the flesh with its passions and desires.
So, you are looking at the opposite criteria.