May God bless your reading.
“1. God did not make salvation available to anyone until 2000 years ago, effectively condemning the 200,000-ish years of humans that came before Jesus.”
Question: Have you ever heard of a collection of books called "The Old Testament"?
(This is a compilation of books in "The Holy Bible" which predate and prefigure the coming of Jesus Christ.) Christians firmly believe that Old Testament people (folks who lived BEFORE Jesus Christ was born) are indeed recipients of salvation. Thus, your first claim is wildly misguided and false.
“2. God does not make salvation available to those who haven't been reached by Christian proselytizers.”
Obviously, this is untrue. (Having now been introduced to the Old Testament you can surely see this.)
“3. The Crucifixion of Jesus is fundamentally unnecessary. If the Christian God is real, he could have granted us salvation without torturing anyone to death. The death of Christ is, at best, purely symbolic, and choosing torture for your symbolic gesture is the act of a psychopath--not a loving exemplar of morality.”
The Christian faith isn't about what God "could have" done (or what you or I think He should've done); but rather it concerns itself with what God actually did or does. (I find the argument, "There is no God because if there was He would be more like me," to be non-compelling.)
“4. Point 3 is made even worse by that symbolic gesture's apparent lack of efficacy. Well over half of all the humans who have ever lived (more than half, even, of the humans who are alive today) have not accepted Jesus as their savior and either did not or will not receive salvation as a result.”
This statement is based upon sheer ignorance. How can you possibly know—or even imagine or guess—how many or what percentage ("well over half" you said!) of humans past, present, and future are or will be saved?
The four “points” are quite telling. It seems to me that many atheists have grown so accustomed to their caricatures of Christianity that they confuse fabrications with realities.
Thus, while certain atheists fancy themselves to be “Brights,” when it comes to the actual content of the Christian faith, it seems many, if not most of them, are rather dim.