yes exactly, we are called to test the spirits not judge the sins.
1 John 4:1-3
Dear friends, do not believe every spirit, but test the spirits to see whether they are from God, because many false prophets have gone out into the world. This is how you can recognize the Spirit of God: Every spirit that acknowledges that Jesus Christ has come in the flesh is from God, but every spirit that does not acknowledge Jesus is not from God. This is the spirit of the antichrist, which you have heard is coming and even now is already in the world.
The presence of sin in a persons life does not mean they are not a "true Christian". Every human being on this planet sins.
In fact, when we judge other people for their sins, we judge ourselves because we have the same sinful human nature. The things they are guilty of, we are guilty of because we have all done similar things.
Jesus told us to try the Spirits to see whether a person is born of God, not judge the sins.
Saved people profess and proclaim Jesus Christ is Lord and Messiah who existed for eternity with God and as God, was born of a virgin, lived a sinless life, performed many miracles, predicted his own death and resurrection, died an atoning death by crucifixion, resurrected from the dead and ascended into heaven and sat down at the right hand of God.
Saved people confess Christ.