It's not so silly when you analyze it. There are basically three belief systems: Earn your way to heaven, Atheism, be forgiven.
If God is a perfect Holy God who knows no sin, and if He judges by His own standard and not some bell curve of humanity, then it is reasonable that God will find us guilty.
It is also reasonable that God through his foreknowledge has already judged us and declared that there are "none righteous" like the Bible says. If so this rules out option 1, earning your way.
If God exists, and has in fact revealed Himself to man, that rules out #2 Atheism.
That leaves forgiveness. If there is only one plan for forgiveness. Then Christianity alone is the answer to man's sin delimma.
It's not about "faith being weak" and finding comfort in everyone else believing too. It's about loving your neighbor enough to broach the subject, knowing that you will probably have to endure his insults for doing so. But doing so anyway for the long odds that he might just listen.