The Talmud relates that Onkelos the Proselyte raised Jesus from the dead (see Christians, even we believe in the Resurrection, just a bit later than you and in different circumstances) and asked him a few questions (Gittin 57a):
Onkelos then went and raised Jesus the Nazarene from the grave through necromancy. Onkelos said to him: Who is most important in that world where you are now? Jesus said to him: The Jewish people. Onkelos asked him: Should I then attach myself to them in this world? Jesus said to him: Their welfare you shall seek, their misfortune you shall not seek, for anyone who touches them is regarded as if he were touching the apple of his eye. Onkelos said to him: What is the punishment of that man (a euphemism for Jesus himself), in the next world? Jesus said to him: He is punished with boiling excrement. As the Master said: Anyone who mocks the words of the Sages will be sentenced to boiling excrement.
Is this meant in literal sense? I don’t think anybody knows with certainty, and to the best of my knowledge, we can’t raise Jesus like Onkelos allegedly did. But the Rambam explains it is an allegory for the warped mind of those who mock the Sages. In his words (Introduction to Mishnah) :
They said "Anyone who mocks the words of the sage is judged in burning excrement..." – and there is no greater “burning excrement” than the foolishness that brought him to mock them (the Sages)…And therefore, you will not ever find one who distances their words except for a man seeking desire and who chases material pleasure, who has not enlightened his heart with any of the bright lights.
The idea is that this is not a penalty, but a natural consequence. It is the foolishness of the fool (the mocker, or for our purposes, the atheist) that tortures him. Anecdotally speaking, from my interactions with atheists, this is accurate. They appear to be deeply troubled souls, experiencing tremendous inner turmoil. Frankly, they would probably be flattered to be compared to Jesus.
But why this allegory? What is special about bubbling feces, and what does it have to do with a twisted mind?
We know that the Torah is compared to many beneficial things. Bread, meat, wine, food, water, honey. If these things are the Torah, then what is the opposite of the Torah, such as atheism? The Rambam explains in Shemoneh Perakim:
Now, just as those, who are physically ill, imagine that, on account of their vitiated tastes, the sweet is bitter and the bitter is sweet—and likewise fancy the wholesome to be unwholesome—and just as their desire grows stronger, and their enjoyment increases for such things as dirt, coal, very acidic and sour foods, and the like—which the healthy loathe and refuse, as they are not only not beneficial even to the healthy, but harmful—so those whose souls are ill, that is the wicked and the morally perverted, imagine that the bad is good, and that the good is bad. The wicked man, moreover, continually longs for excesses which are really pernicious, but which, on account of the illness of his soul, he considers to be good….Likewise, just as when people, unacquainted with the science of medicine, realize that they are sick, and consult a physician, who tells them what they must do, forbidding them to partake of that which they imagine beneficial, and prescribing for them things which are unpleasant and bitter, in order that their bodies may become healthy, and that they may again choose the good and spurn the bad, so those whose souls become ill should consult the sages, the moral physicians, who will advise them against indulging in those evils which they (the morally ill) think are good, so that they may be healed by that art of which I shall speak in the next chapter, and through which the moral qualities are restored to their normal condition.
The spiritually ill prefer eating dirt and coal to bread and meat. But no matter how hard he tries, the person cannot digest dirt and coal, so it has to go somewhere. The only place for it to go is out. But like a hamster, he returns to feast on his own feces, getting even sicker in the process. Ideally, the solution would be for the patient to consult with a doctor, the sages, to turn away from his harmful practices. But since he mocks the sages, he spurns all assistance, which results in him helplessly stewing in a growing puddle of his own filth. By refusing to get help, he condemns himself to his own fate.
In a previous post, I compared the OTD atheists to the mentally ill. This wasn’t literal, and it wasn’t meant as an insult. To the contrary, it was a statement of empathy for these afflicted souls. But they nevertheless took great offense that I dared to question the messed-up mental processes that led them to their present beliefs, that they could possibly be driven by anything other than a single-minded quest for the truth. As if I’m supposed to just trust them on that. But as you can see, it’s not me! I didn’t invent this idea! It’s the Rambam, and further back, a plausible interpretation of the passage in Gittin. And even atheists respect the Rambam.
"But they nevertheless took great offense that I dared to question the messed-up mental processes that led them to their present beliefs,"
I must have missed your explanation of what's messed up about atheist beliefs. If you can't demonstrate the existence of a deity, then atheism is the logical default position. And remember that you yourself are an atheist with respect to thousands of deities whose existence is attested by others. Just employ the same standards of evidence across the board. It's really not so difficult.
What is mocking of the sages ? Some ( R@L ) would say the Rambams allegorical interpretation of chazal and Tanach is Ch v Sh mockery . Some of what Chazal said about the natural world we now know to be innacurate. Even the Rambam’s calculations of the moled. And the Rambam said Shaidim are allegorical . So it’s fine and good that you quote the Rambam but hard to know what is the line and how to avoid it. We certainly don’t want to boil in real or metaphorical excrement!