What is a meta? Apparently its 1 rune that is so op, it practically wins you the game no matter what

I remember when the 8.23 patch was first live and at the home page said "Is it meta?" when you combine this statement with the fact that DH is so op, the question seems like an absolute joke. is this riot's idea of a prank cause this is the dumbest meta i ever seen. Even if the damage per soul is lowered to 5, its power is gonna be nearly the same, especially when this rune can be activated every minute if the enemy player doesn't back. It sure feels great when a game can be determined by how many people pick a certain rune in the game.