Then why do Christians have to go around threatening their god will burn people for ever if they don't convert?
Christians do not have to do that - at all - neither necessary nor useful. Matters not to one who knows the difference between a supposed contemporary human threat and a Biblical truth.
Before you can call it a truth, you need to present sufficient evidence. Until then, it's just a Christian scare tactic.
There is no proof the sun will cast its light every day.
Ecc 10:2 The heart of the wise inclines to the right, but that of a fool to the left.
A Nation which leaves God behind is soon left behind.
"The Lord never asked anyone to be a tax collector, lowyer, or Redskins fan".