Couldn't hell just be separation from God?

A lot of atheists (myself included) believe that the doctrine of infinite torture in hell for finite sins in this life is drastically, ludicrously unjust. Some Christians will rebut this by offering the theory that hell isn't really a Dante-esque place of endless sadism and torture; rather, the torture comes simply from being separated from God, and that's all.

Contrary to this comparatively pleasant idea, however, there are quite a few verses in the New Testament (as ol' Hitch was so fond of saying, it wasn't until "gentle Jesus, meek and mild," that the concept of eternal torture was introduced) which explicitly reference a fiery-torture version of hell. I'll be honest, I was surprised myself by how many there were. Off the top of my head, I could only think of one in the gospels, and a few in Revelation. So I did some googling, and it turns out I was indeed missing quite a few. I'm gonna start with the “primary source” quotations, i.e. the words of Jesus, but I'm also gonna start with the weakest one from that group...

(All bold emphasis is my own.)

Luke 16:24 [in the story of the rich man and Lazarus] - So he called to him, 'Father Abraham, have pity on me and send Lazarus to dip the tip of his finger in water and cool my tongue, because I am in agony in this fire.'

…Now, of course, this one is from a parable, so it’s easy to dismiss descriptions here as just being poetic imagery. Are we really expected to believe that people who are punished with eternal separation from God are literally within shouting distance of heaven? Not likely. So, taken individually, the description of fiery agony here could be dismissed as just poetic imagery, but it just so happens that this description meshes quite well with plenty of references to hellfire that are much more straightforward…

Mark 9:43 - If your hand causes you to stumble, cut it off; it is better for you to enter life crippled, than, having your two hands, to go into hell, into the unquenchable fire,

Matthew 5:22 - But I say to you that everyone who is angry with his brother shall be guilty before the court; and whoever says to his brother, 'You good-for-nothing,' shall be guilty before the supreme court; and whoever says, 'You fool,' shall be guilty enough to go into the fiery hell.

Matthew 13:40-42 [Jesus describing the real meaning behind the parable of the wheat and the tares] - ⁴⁰"So just as the tares are gathered up and burned with fire, so shall it be at the end of the age. ⁴¹"The Son of Man will send forth His angels, and they will gather out of His kingdom all stumbling blocks, and those who commit lawlessness, ⁴²and will throw them into the furnace of fire; in that place there will be weeping and gnashing of teeth.

Matthew 18:9 - If your eye causes you to stumble, pluck it out and throw it from you. It is better for you to enter life with one eye, than to have two eyes and be cast into the fiery hell.

Matthew 25:41 - Then He will also say to those on His left, 'Depart from Me, accursed ones, into the eternal fire which has been prepared for the devil and his angels;

…So, that seems pretty conclusive to me already, but if you go outside of the gospels, there are even more straightforward references to a fiery hell…

James 3:6 - And the tongue is a fire, the very world of iniquity; the tongue is set among our members as that which defiles the entire body, and sets on fire the course of our life, and is set on fire by hell.

Jude 1:7 - just as Sodom and Gomorrah and the cities around them, since they in the same way as these indulged in gross immorality and went after strange flesh, are exhibited as an example in undergoing the punishment of eternal fire.

Revelation 14:9-10 - ⁹Then another angel, a third one, followed them, saying with a loud voice, "If anyone worships the beast and his image, and receives a mark on his forehead or on his hand, ¹⁰he also will drink of the wine of the wrath of God, which is mixed in full strength in the cup of His anger; and he will be tormented with fire and brimstone in the presence of the holy angels and in the presence of the Lamb.

Revelation 20:15 - And if anyone's name was not found written in the book of life, he was thrown into the lake of fire.

Revelation 21:8 - "But for the cowardly and unbelieving and abominable and murderers and immoral persons and sorcerers and idolaters and all liars, their part will be in the lake that burns with fire and brimstone, which is the second death."

…So there you have it. Eleven different verses (not counting whatever parallel verses there may be to some of the Gospel quotes) which very specifically and directly describe fire as a fundamental characteristic of hell. Unless there’s some other verse I don’t know about which specifically says that all of these verses are just speaking symbolically, then I don’t see how you could possibly hold the position that the doctrine of “mild hell” is Biblical, in light of all these verses.