In Loving Memory?

Okay, what the heck is with the epitaphs on the back windshield of people's cars? I'm seeing it more and more lately.

In Loving Memory

So and So

19whatever-20whatever

Blah Blah Blah

Really? I saw two on one pick up truck rear window today. It just boggles my mind. How does a decal on the back of your SUV honor the dead? The In Loving Memory part is really what gets me. What is In Loving Memory--the car?--the decal? I just don't get it.