Hi. I am not sure if I properly understand your question. Could you simplify it a little? Nevertheless, here’s some thoughts I have about your post.
First we must remember that Jesus makes statements that sometimes sound contradictory because He means different things in different contexts. For instance, in one place He might say that He has not come to judge the world (for instance John 12:47), and in another place He might say that He will come to judge all nations (like Matthew 25:31-33; Revelation 22:12-13).
In the first case, Jesus is emphasizing that His primary mission on earth is not to condemn but to win people back to the Father, to forgive sins (through His own sacrificial death), to sanctify, to redeem, to save.
In the second case, Jesus is saying that He will be the one on the throne judging all the nations at the end of time/Last Judgment/Second Coming. His actions in the end times will be different from His actions on earth 2000 years ago.
In the passage you cited, Jesus wants people to understand that He is proclaiming (and that He Himself is) the definitive divine revelation of the Father given to man. Because Jesus is the way, the truth, and the life, we must believe in Him, know Him, love Him, and serve Him in order to have a proper relationship with God. Jesus, the incarnate Word, perfectly reveals the Father to us. We would not know the Father if it were not for the Son who has revealed Him to us. Jesus uses images of light to describe what it means to come to know God because knowing God is “enlightening” – it is a kind of knowledge that leads to wisdom, understanding, and ultimately our salvation (if we respond to His free gift of grace), and it makes sense of our confusing world. Knowledge of who God is and what He wants from us sets us free to be what He designed us to be and to act in accordance with our natures. Jesus is the light of the world because He is the source of its salvation, the victor over the darkness of sin, evil, and death, and because He makes sense out of human history. Without the light of Christ, the Old Testament, human suffering, and our very lives would remain a complete enigma, if not totally meaningless.
I do not think this text is specifically talking about Purgatory or Protestants, but I could be missing something.
It seems to be emphasizing this point: to reject Jesus is to reject God, or at least the light that comes from knowing God’s perfect self-revelation.