The deep religious hatred towards another human being he has experienced must be exposed again and again. The verbatim quoting of original messages is a powerful way to do just so as it leaves nothing unclear - these Christians say in expressis verbis what they think about him as a person and about his views.
Hell as Devil's paradise
Many of the messages threaten Dawkins with sudden death, misfortune and eternal tortures in Hell planned by the Devil - or in some or the more twisted messages by God himself.
The deep rooted misunderstanding that Hell is Devil's paradise where he is allowed to do what he likes most, eternally torture condemned humans, is reflected in many of the hate messages. What could be a better place for the fallen angel, Satan, then a huge torture cell where nothing limits the pain he can inflict on the victims who never die whatever is done to them?
This mistaken view of Hell is not Biblical but rather reflects the times during which western society used torture and painful execution methods against serious criminals. Since this goes way back to the Byzantine and Roman periods and continue way until Enlightenment began to change perceptions of criminal punishments in 18th century, the reality of judge, condemnation and punishment must be deeply rooted in human psyche, in the common memes to use terminology of cultural heritage developed by Dawkins.
Lake of burning sulfur
In contrast to the medieval torture chamber where Devil enjoys all sadistic games he can invent the Book of Revelation simply says that at the end he is thrown into a fiery lake and that's it, second death rather than place for his SM games.
When the thousand years are over, Satan will be released from his prison and will go out to deceive the nations in the four corners of the earth—Gog and Magog—and to gather them for battle. In number they are like the sand on the seashore. They marched across the breadth of the earth and surrounded the camp of God’s people, the city he loves. But fire came down from heaven and devoured them. And the devil, who deceived them, was thrown into the lake of burning sulfur, where the beast and the false prophet had been thrown. They will be tormented day and night for ever and ever.This is no paradise for Devil but his place of eternal punishment with the beast and the false prophet.
Rev 20:7-10 NIS
Unfortunately the Book of Revelation sees also human beings in that fiery lake
Those who are victorious will inherit all this, and I will be their God and they will be my children. But the cowardly, the unbelieving, the vile, the murderers, the sexually immoral, those who practice magic arts, the idolaters and all liars—they will be consigned to the fiery lake of burning sulfur. This is the second death.You say "Revelation is such a difficult book to understand".
Rev 21:7-8 NIS
But still not a laughing matter, however stupid email messages Christians send to others.