DC

I recently played a game where I had an unfortunate disconnect for approximately 5 minutes. The game was going well, and after I reconnected, we managed to win. Despite this, I was awarded a D- and given negative LP. Overall, I contributed even KDA, had reasonably strong kill involvement, and overall influenced the game towards our win sufficiently that no one on my team was upset.

Is this really a reasonable outcome in Riots' mind?