How do you consolidate that absolute judgement with those who left the church, but later returned and remained faithful?
I must have just glanced past this question without ever answering before, sorry about the late answer. I honestly don't know if I understand your question. I kind of need to know what "absolute judgement" is when you used it, but if you mean the wrath of God that abides over every single one of us because of Adam and original sin, the very wrath poured out in full on Jesus as He hung on that cross, then I don't believe the way you asked the question reflects a "born again" perspective. Please don't be offended and let me explain what I mean.
You're asking "How do you consolidate that absolute judgement with those who left the church, but later returned and remained faithful?", in this scenario if I'm understanding it is, if a person comes and "joins the church", then leaves to return to sin only to end up back with Jesus until the end. If that right then honestly from a spiritual perspective don't understand how this could even be confusing, but I believe this could be one of two different possibilities.
First one is he was not truly born again the first time. This is my testimony and I share this all the time. I went up front when the pastor called, repeated the prayer, and was dunked under water in front of everyone for good measure, and was not saved. God used this for a reason of course, as I would put forth in the hypothetical, he wasn't saved at first, returned like a dog to the vomit to his sin, God used that as part of his will and glory to teach him the difference and then later draws him in, in truth, and resurrects his spirit reconciling it back to His, as we were created to be, making him whole in a way impossible by the flesh.
So really the guy thinks he was saved at first, but wasn't. That being part of Gods plan to help teach and impart wisdom he can now share to draw others in. It's ALL His plan, I think we lose the meaning of what sovereign actually means a lot.
The second is very much the same kind of story only, the person is born again in truth. Praise Jesus. Does this make us 100% perfect then and there? No it is just the beginning of sanctification. So if this person returns to the vomit, he does so with our Lord in him now, Gods Spirit guiding him, convicting him when he's wrong and leading him back.
I honestly feel this kind of thinking you're putting forth in this question (this question alone, not by any mean speaking about you in general, so please don't take it like that) is honestly from a perspective of pop Christianity that says that, "no matter what if you repeat these words you are saved and no one can tell you different. Not only that I want you to know you're still going to sin. All of us do. Just look at Paul in Romans talking about what a wretched man he is."
While there is not much in this statement that is technically wrong, aside from the lie that repeating words will save you, it's just the gospel and resulting power of God in our lives, being framed the way they are here, I believe (because it happen to me first hand), creates false converts who don't believe in judging anyone for anything, at anytime, and it's created a safe spot to keep our sins in, never going out to talk about Him, never recognizing "my way" for the path straight to death that it is, and never repenting and turning from "my way" to Him and the gift of Jesus perfectness washing you clean in the eyes of the Father forever. Being born again is the literal resurrection of our dead spirit opening our eyes to the truth of the spirit in reality, testifying of the Father and Son, but not only that but you now are plugged into God, by His Spirit, for the first time, now able to live life in a way that can please our Father. The closest I can explain my rebirth to others is that it was as radical and insanely mind blowing as waking up out of the Matrix would be in real life. It is truly that radically real. We now desire this and it's only by His power and ALL works for His glory, even when, and especially when we walk away proud but come back humbly on our knees. Anyway that my thoughts on the topic, thank for the question and have a great day.
So not bad for a 1 sentence question.