“Much confusion and misunderstanding has been caused through the early translators of the Bible persistently rendering the Hebrew Sheol and the Greek Hades and Gehenna by the word hell. The simple transliteration of these words by the translators of the revised editions of the Bible has not sufficed to appreciably clear up this confusion and misconception.”—The Encyclopedia Americana (1942), Vol. XIV, p. 81. Translators have allowed their personal beliefs to color their work instead of being consistent in their rendering of the original-language words. For example: (1) The King James Version rendered she’ohl′ as “hell,” “the grave,” and “the pit”; hai′des is therein rendered both “hell” and “grave”; ge′en·na is also translated “hell.” (2) Today’s English Version transliterates hai′des as “Hades” and also renders it as “hell” and “the world of the dead.” But besides rendering “hell” from hai′des it uses that same translation for ge′en·na. (3) The Jerusalem Bible transliterates hai′des six times, but in other passages it translates it as “hell” and as “the underworld.” It also translates ge′en·na as “hell,” as it does hai′des in two instances. Thus the exact meanings of the original-language words have been obscured.

Because it's just a burning mud hut.

Because so many people confuse Hell with the Lake of Fire.

In addition to Seahorse's excellent points ... Because most people don't read the Bible, let alone study it for its doctrine of Hell, but merely believe what they think others have said it teaches, and when they say "the Church says ..." or "pastors/theologians say ..." the truth is usually "this is what I got from my mother: ..." And then there's the effect of popular entertainment. 80 years ago G.B. Shaw wrote, "Today almost all of what everyone thinks they know of Hell comes out of the mouths of an Italian [Dante] and an Englishman [Milton] and to this day everyone of them thinks it's in the Bible." Today, The Inferno and Paradise Lost have been replaced with CONSTANTINE and THE OMEN.

Because, just like everything else in the bible, it has been taken and interpreted by individual religions in an attempt to make their way seem like the one right and true way.