I always wondered why punishing a team for something that is outside their control is acceptable, but punishing leavers and afkers is not.
People say it can be abused, but that's more so because premades are so prevalent. Riot basically set up this toxic environment to become even more toxic and now they're in a pigeonhole about it.
Here's the thing though, it may be abusable, but it'd also be very easy to see when this is happening for investigators. Someone afk's on enemy team to try and prevent lp loss. Leaverbuster already can keep track of this. If someone gets flagged then they mark the associated teammates as well. If those teammates are flagged in leaver-teams 3 times, they open a ticket to investigate. Boom. A 5-man premade gets a temp ban and receives the full lp losses. Sure, some people will still slip through the cracks, but it won't be anything like the nightmare people envision if Riot cared about the ranked experience.
I said if though and with the advent of dynamicq I guess we see where they stand on how seriously they take ranked.