Because it wasn't about getting mugged and smiling about it. You're quoting the Sermon on the Mount like it’s a Reddit-tier guide to being a doormat, when it's actually a total rejection of the pagan honor code. Christ didn't come to reinforce tribal vengeance or survival-of-the-fittest morality. He came to break that cycle entirely.

>Turning the other cheek
It's not passivity. It’s defiance. In Roman society, a backhand was a way to humiliate someone beneath you. Turning the other cheek forces your attacker to treat you as an equal.

>Giving your cloak
You shame your oppressor by exposing the injustice of their greed.

>Loving your enemy
That’s the nuclear option; not emotional surrender, but the radical assertion that no tyrant can control your soul.

The early Church spread not because it offered political power or wealth (quite the opposite), but because people saw in it a dignity, a coherence, and a supernatural strength that pagan Rome couldn’t touch. Martyrs went to their deaths forgiving their killers, and the blood of those martyrs seeded an empire-wide conversion. If Christianity were what you describe, a pathetic call to roll over and die, it wouldn’t have survived the first century. What you’re mocking isn’t Christianity, it’s a caricature. The real thing overturned the most powerful empire in the world without a single sword. Maybe ask "how" before you scoff at "why."