Why do 8 inning losses count as complete games?

The other team pitched 9 innings

If the home team doesn't bat in 9th inning cause already have the lead. Then visiting teams pitcher gets complete game loss if was the only pitcher for his team.

because they completed the game?

because they pitched the complete game

Why do 9 inning wins count as complete games?

You only pitched half the game. You didn't pitch when your team was batting.

because that is the end of the game... the game has been completed


complete game does not mean 9 innings.... it could be 10, 11, 12,13 a million less than 9 if it gets called due to rain or something else....

but the pitcher only pitched 4-4.5 innings, thats not a full game.