You have judged "people" as teaching sinless perfection. Would you back up this judgement of "people" by quoting someone who you say does this. Christ did this, but I have seen people accused of it, but never have I seen anyone who actually did this except Christ.
Christ told us what to do about our sin, Christ repeated it so you wouldn't miss it or wonder about how sin in our life affects their walk with Christ as a Christian. Christ said "repent". Christ wanted us to try our best to follow our Father, for when Christ taught to greet all people with the acceptance the Father has, Christ said in Mathew 5:48--
Be perfect, therefore, as your heavenly Father is perfect
Are you a member of the Christianity Board? You can read their posts for yourselves there. I will quote some of these folks who promote sinless perfection:
GENREV2 - Do you claim to be 100% without any sin, like Christ, from moment to moment 24/7..?
Michiah-Imla - Yes.
Episkopos - Do you believe you can walk like Jesus without sin? Access into that salvation walk by grace is through faith. When we enter INTO Christ we put on His perfection. We walk as He walked. Of course, very few will do this. Jesus said that few would enter into the narrow way and walk the narrow path. Any unbeliever can claim to be in their own sinful strength. That's true. As long as we are not PERSONALLY covered by grace...we will sin. When we sin it shows we are still under the law. What law? The law of sin and death.
Bible Highlighter - The Bible does teach that it is possible to be perfect and to sin no more - if you believe the Bible.
Peterlag - I cannot sin because I'm born again.
There are more, but this is sufficient.
Those who promote sinless perfection will often cite Matthew 5:48, in which Jesus says: “You therefore must be perfect, as your heavenly Father is perfect.” Sinless perfectionists will then claim that we “must” be as perfect as God the Father (implying sinless perfection) if we are to be saved. However, that is not what the passage is saying. In context, this passage is talking about love.
Matthew 5:43 - "You have heard that it was said, 'You shall
love your neighbor and hate your enemy.' 44 But I say to you,
love your enemies, bless those who curse you, do good to those who hate you, and pray for those who spitefully use you and persecute you,
45 that you may be sons of your Father in heaven; for He makes His sun rise on the evil and on the good, and sends rain on the just and on the unjust. 46 For if you love those who love you, what reward have you? Do not even the tax collectors do the same? 47 And if you greet your brethren only, what do you do more than others? Do not even the tax collectors do so? 48 Therefore you shall be perfect, just as your Father in heaven is perfect.
Jesus is talking about how to love properly, the way God does. The teaching is that to love as God does, we should also love those who don’t love us back, even love those who hate us. Jesus calls this kind of love "perfect" love. The word used for "perfect" in this passage is "teleios" and the definition is: Fully developed. Mature in mental & moral character. Full development, growth into maturity of godliness. Signifies consummate soundness, and includes the idea of being whole. Jesus is saying that to have fully developed mature love, as God desires, we must love our enemies. That is a lot different than saying to be saved you have to be perfect, sinless, without fault or defect, flawless in every way, as sinless perfectionists teach.