You might want to learn what the age of accountability is.
The age of accountability varies according to the person's variables.
We all have an age of accountability.
If I find a native walking along the banks of some remote river, who has never heard of Jesus, he will someday reach that age of accountability and have to account for it ... if he hasn't already.
And what happens when he says to God, "Well, how could you expect me to believe in you when I'd never even heard of you?"
Does God say, "Well you should have believed in me anyway!" and send the poor fellow to Hell, or does God say, "Well, I can't expect you to believe in me if you were unaware of me," and then let the guy in?
They are words that are coined to help facilitate a conversation.
Instead of saying "the snatching away" or "the harpazo" (or whatever it's called), its much easier to just say "the rapture."
Same for the Trinity.
Instead of saying "the Godhead" or the "triune Godhead", it's much easier to just say "the Trinity."
So when you say, "The Bible doesn't say "rapture" ... yet the Rapture is a major doctrine ... The Bible doesn't say "Trinity" ... yet the Trinity is a major doctrine", you really mean that while that exact phrasing doesn't appear in the Bible, the IDEAS behind them do appear in the Bible.
Could you please show me which passages talk about these concepts?
Well ... for the record ... thanks to the age of accountability, children who are aborted go directly to Heaven;
So then why do so many Christians have a problem with abortion? You are GUARANTEEING that the baby is going to heaven! Why let it be born where it runs the risk of becoming a hell-bound atheist?
and the chances of ... a remote spear chucker, or someone raised in another religion are better than an [unregenerate] Internet scientist's.
So aren't the missionaries who go to bring God to those "remote spear-chuckers" doing those spear chuckers a disservice? While the spear chuckers remain ignorant of God, their entry to Heaven is GUARANTEED! But as soon as the missionary tells them about Jesus, the spear chucker has the ability to reject the missionary's claims and thus risks eternal damnation in hell!
So isn't it better to leave the natives in their blissful ignorance and be happy that their ignorance guarantees them entry to Heaven? Why take the risk of sending them to hell?
Of course, you can deny it, then stand around and ask others what happens to babies that die? or whine how mean God is.
I'm not going to deny it. I'm just going to point out that the extension of this logic leads you to conclude that abortion is good (because it sends babies to Heaven before they get a chance to reject God) and missionary work is bad (because it gives people the option to reject God and thus go to hell).