Lost LP Despite Win

I've just played a game and had a disconnect, probably about 5 minutes due to a power outage. I immediately logged back in and finished the match with a win. Not just that, but one can look that I actively contributed to it. However, at the end of the game, I lost 18 LP instead of gaining any.

I understand that this is due to LeaverBuster, but honestly, that's just kinda messed up. Why am I being punished for something that:

1. is out of my control?
2. did not affect my team's win?
3. was remedied in a matter of minutes?
4. should not happen on a regular basis?

I feel like a better explanation than "It's leaver buster" is in order ...