In this case it is a bit obvious, but often what an archeological find of this type tells us, is that something was important enough in that society for an arti

In this case it is a bit obvious, but often what an archeological find of this type tells us, is that something was important enough in that society for an artist to take the time to make a relief depicting it. It is not so much "people were kissing", but that "people were celebrating kissing as an integral part of copulation" at that time, showing that society appreciated the intimacy, rather than just treating it as the more animal pump and dump, then get on with your day.