Clearly not getting anywhere with the rest
You ain't getting nowhere...because you can't rebuttal the truth.
The correlation is this: You claim that people who once believed and left, never 'really' believed. Is it your contention that they didn't become disciples upon first believing?
As far as we, in our finite knowledge and presence could tell, they did...but in God's infinite knowledge and presence, maybe they didn't.
Let's go at this another way:
When you were young, you likely believed in Santa, the tooth fairy, the Easter bunny, or any other manner of fairy tales based on your culture. When you grew up, you stopped believing because you discovered evidence that overrode your previous belief and had no choice but to change your stance.
What you are saying is tantamount to claiming that children never really believed in Santa/EasterBunny/etc., and were somehow 'faking' it. Just like former Christians who I guess you think were 'faking' it.
I'm trying to drill down to why some Christians make this ridiculous claim that previous believers never really believed?
I think a better analogy would be a woman who thinks she found the man of her dreams..a man who treats her how she believes she deserves to be treated..
But over time, the man begins to physically abuse her and mistreat her in more ways than one..
Then the woman begins to think..."this man was never the man of my dreams"..because in her "dreams", the man didn't treat her that way..so the man in her dreams and the man in real life are two different men.
So the woman ultimately decides that the man was never "the one"...because "the one" will never treat her that way.
I don't believe your analogy is accurate, because, as I look from my Christian "lens", Christianity is true...and since it is true, there is no amount of evidence that you can find which will negate its truth value..
So if you decide to leave, it isn't based on any adequate evidence to the contrary...you left because of something "else".
A true believer ain't going nowhere.