It's the way we were created. Eve was created after Adam, to be his partner and companion.
It's not saying that we are inferior to men in the least, just that we have a different role.
This may not completely fall under it, but for the record, most of the "rules" that seem ridiculous to us in the Old Testament fall under the Old Law, and (in the New Testament) Romans 7:6 tells us [that in Jesus' dying for us on the cross]:
"But now we have been released from the law, for we died to it and are no longer captive to its power. Now we can serve God, not in the old way of obeying the letter of the law, but in the new way of living in the Spirit."
Meaning, we don't have to follow those silly old laws anymore.