That’s picking on symbols, but I love it anyway.
Why do people use love locks as a symbol for their relationship?
They symbolize lack of freedom. Prisoners and kidnapped children are rotting behind doors closed with locks like these. You use them for your basement to store stuff that you never need anymore, but which you don’t want anyone else to take either. These locks are used to close the barn door to keep the cattle in, so that the cows and the sheep won’t escape slaughter.
Throwing away the key is even worse. It’s the nonverbal way of saying: “That’s it. You are no longer in control of your own life. You are going to die here, no matter what.”
You would never use a lock for somebody whom you truly cherish and respect, in whose liberty you believe and whom you trust.