Because it is a piece of FICTION, based on the false doctrines of an apostate religious system that stole "Hell" from the Greeks and Romans.
Revelation 20
12 And I saw the dead, the great and the small, standing before the throne, and scrolls were opened. But another scroll was opened; it is the scroll of life. And the dead were judged out of those things written in the scrolls according to their deeds. 13 And the sea gave up those dead in it, and death and Ha′des gave up those dead in them, and they were judged individually according to their deeds.
Please notice Hades or Hell as the KJV renders it GIVES UP all that are in it.
Rev 20:13 And the sea gave up the dead which were in it; and death and hell delivered up the dead which were in them: and they were judged every man according to their works.
And then notice that Death and Hell are destroyed forever...
Rev 20:14 And death and hell were cast into the lake of fire. This is the second death.
That is why the faithful man Job said to God
13 O that in She′ol you would conceal me,
That you would keep me secret until your anger turns back,
That you would set a time limit for me and remember me!
KJV
Job 14:13 ¶ O that thou wouldest hide me in the grave, that thou wouldest keep me secret, until thy wrath be past, that thou wouldest appoint me a set time, and remember me!
Hell is a translated word for either Sheol, from the Hebrew or Hades from the Greek.
As the KJV says the Grave is Hell. All humans since Adam and Eve that have died from their sin end up there.
And the apostle Paul wrote the following:
15 and I have hope toward God, which hope these [men] themselves also entertain, that there is going to be a resurrection of both the righteous and the unrighteous.
KJV
Act 24:15 And have hope toward God, which they themselves also allow, that there shall be a resurrection of the dead, both of the just and unjust.
So, since sin results in death, then we are in the grave that is common to men, and the fairy tale about 7 youths have NO basis in scripture for being taught. Both the righteous, like David, Abraham, Moses, and the unrighteous, the many billions who have never even hear of the Bible, will be back to life.
http://www.watchtower.org/e/bh/article_06.htm