If there is a hell, it's listening to the religious people.
On a more serious note -- Jesus came to save the world, but whosoever does not believe stands condemned already. A lot of people don't know that. That is to say, people trump John 3:16 as proof that the bible isn't seeking to condemn people, yet in 3:18, that is exactly what it says. This, by the way, is the verse that the Phelps use to justify that the world is doomed.
Phelps' eschatology is for **** by any standard, even those of primitive Baptists. If you're taking his word for
anything, on any subject, may the fleas of a thousand camels infest your crotch for being a total nitwit.
The existence of Hell actually rests on a very small number of biblical passages, the most prominent of which is the whole "depart from me ye cursed into the lake of fire prepared for Satan" blahblah. A fairly sound case can be made that the second covenant removes Hell from the equation (possibly entirely), although making that case is not popular.
Assuming you buy into this stuff.