"Whom we preach, warning every man, and teaching every man in all wisdom; that we may present every man perfect in Christ Jesus:" (Col 1:28)
Again, context. Notice what Paul has already just stated:
Col 1:9 And so, from the day we heard, we have not ceased to pray for you,
asking that you may be filled with the knowledge of his will in all spiritual wisdom and understanding,
Col 1:10
so as to walk in a manner worthy of the Lord, fully pleasing to him: bearing fruit in every good work and increasing in the knowledge of God;
...
Col 1:21 And you, who once were alienated and hostile in mind, doing evil deeds,
Col 1:22 he has now reconciled in his body of flesh by his death,
in order to present you holy and blameless and above reproach before him,
Col 1:23
if indeed you continue in the faith, stable and steadfast, not shifting from the hope of the gospel that you heard, which has been proclaimed in all creation under heaven, and of which I, Paul, became a minister.
...
Col 1:28 Him we proclaim,
warning everyone and teaching everyone with all wisdom,
that we may present everyone mature in Christ. (ESV)
Notice the progression of this introduction. First, Paul and Timothy pray that the believers at Colossae "may be filled with the knowledge of his will in all spiritual wisdom and understanding." Why? So that they "walk in a manner worthy of the Lord, fully pleasing to him." This likely hints at the reason, or one of the reasons, for his letter.
Second, if they "continue in the faith," they will be able to be presented "holy and blameless and above reproach before him." So, there clearly is something they have to continue to do
in order to be presented "holy and blameless." Third, why should Paul and Timothy be warning believers? What are they to be warning believers of? Does one warn others of good things, such as already being perfectly sinless? That would make no sense. One warns of danger, such as not living the faith as believers should be living, which would be committing sin.
Fourth, the same Greek word can be translated as "perfect," "mature," or "complete." Given the above context, it is could easily be translated as "mature" or "complete" as that fits with what Paul writes in verse 9. It we take it as "perfect," it would be in reference to when they stand before Christ. But notice that Paul doesn't say they are perfect now, it is clearly implied that it is something yet to be accomplished.
So, what is the issue? Look at chapter 2:
Col 2:6 Therefore, as you received Christ Jesus the Lord,
so walk in him,
Col 2:7 rooted and built up in him and established in the faith, just as you were taught, abounding in thanksgiving.
Col 2:8
See to it that no one takes you captive by philosophy and empty deceit, according to human tradition, according to the elemental spirits of the world, and not according to Christ.
...
Col 2:18
Let no one disqualify you, insisting on asceticism and worship of angels, going on in detail about visions, puffed up without reason by his sensuous mind,
Col 2:19 and not holding fast to the Head, from whom the whole body, nourished and knit together through its joints and ligaments, grows with a growth that is from God.
Col 2:20
If with Christ you died to the elemental spirits of the world, why, as if you were still alive in the world, do you submit to regulations—
Col 2:21 “Do not handle, Do not taste, Do not touch”
Col 2:22 (referring to things that all perish as they are used)—
according to human precepts and teachings?
Col 2:23
These have indeed an appearance of wisdom in promoting self-made religion and asceticism and severity to the body, but they are of no value in stopping the indulgence of the flesh. (ESV)
First, why the need to remind these believers to walk in Christ, if they are already perfect and walking in the light, as you keep saying? Second, we see that the reason for writing appears to be that there were teachings in the Colossae church that were based on "philosophy and empty deceit," "human tradition," and "elemental spirits of the world," which clearly were "not according to Christ." This is supported by verse 20, where Paul goes further and states that these believers were actually submitting "to regulations," as though they "were still alive in the world" despite having "died to the elemental spirits of the world."
Third, more than that, these "human precepts and teachings" that they were submitting to, have "no value in stopping the indulgence of the flesh." Why would Paul mention that these human teachings have "no value in stopping the indulgence of the flesh"? We see that in the next chapter:
Col 3:3
For you have died, and your life is hidden with Christ in God.
Col 3:4
When Christ who is your life appears, then you also will appear with him in glory.
Col 3:5
Put to death therefore what is earthly in you:
sexual immorality, impurity, passion, evil desire, and covetousness, which is idolatry.
Col 3:6 On account of these the wrath of God is coming.
Col 3:7
In these you too once walked, when you were living in them.
Col 3:8
But now you must put them all away: anger, wrath, malice, slander, and obscene talk from your mouth.
Col 3:9
Do not lie to one another, seeing that you have put off the old self with its practices
Col 3:10
and have put on the new self, which is being renewed in knowledge after the image of its creator. (ESV)
Verses 3 and 4 make it clear that he is addressing believers. So, why in verse 3 is Paul telling these believers to "Put to death therefore what is earthly in you," if, as you claim, that has already been done completely and all believers are perfectly sinless? Notice the list of things that these believers were doing: "sexual immorality, impurity, passion, evil desire, and covetousness, which is idolatry."
More than just those, see what else Paul tells these believers to put away: "anger, wrath, malice, slander, and obscene talk from your mouth." He then tells them "Do not lie to one another." Why? Because they "have put off the old self with its practices and have put on the new self." Clearly, all of that shows that Paul was addressing believers, and that these believers were not perfectly sinless. How could that be, if, as you claim, all believers are perfectly sinless?
The answer is in verse 10--"the new self" of each believer "is being renewed in knowledge after the image of its creator," which is what I have been saying. That is the process of sanctification and growing in holiness. And, how is that done? The answer was given in verses 1 and 2:
Col 3:1 If then you have been raised with Christ,
seek the things that are above, where Christ is, seated at the right hand of God.
Col 3:2
Set your minds on things that are above, not on things that are on earth. (ESV)
There is more that could be said just on this letter, but that suffices to show your position simply cannot account for much of what the NT states. Context is king and context makes shows that sinless perfection is not only never taught, but it is clearly taught that believers still struggle with sin while we are being renewed and growing in holiness.