In order to establish whether the concept of hell is childish or silly, first you must define the concept of hell. There are many concepts of hell, even within Christianity, but other religions and belief systems have their own version. And once you establish clearly what you are referring to as childish and inane, is it objectively childish and inane, or just your opinion, the product of your own fruitful imagination? And if the concept of hell as childish, inane and downright silly is an objective truth, what authority established it as such, and is said authority in itself a fact, an undeniable, logically and objectively verifiable, fact?
Come on , now, you know perfectly well that while the intellectual elite of Christianity may have a subtle view of what Hell is, for the great majority of Christians, the word Hell conjures up visions of underground caverns with fires and demons with pitchforks tormenting the sinners.