AFKing in general should have varying degrees - it's okay if someone's internet drops or their PC lags or their electricity goes out - I don't mind that.
When I'm winning bot despite being repeatedly camped by Rammus and my toplaner just yells, "OH SHIT I FORGOT TO COOK GOTTA GO" with caps and stays AFK for 10 minutes, all the while Jayce, now lacking an enemy, decides it's time to gank poor ol' Jinx, I _fucking mind that_.
Of course, Kayle made sure to move the slightest amounts every few minutes so the automated system wouldn't detect her - more than likely avoiding any sort of punishment for this behaviour.
In the meantime, if I want to keep my account and my skins, I have to avoid flaming, despite enemies having said to me "go kys you piece of shit" and me never having received a notification that they were punished for their behaviour.
Riot expects us to keep calm through a storm of bullshit and not flame, yet it does a poor job of letting us know that when someone breaks those rules and flames us to a grave and back is punished for that behaviour and allies just deciding to declare lanes open, int, flame, go AFK intentionally for whichever reason are completely fine by Riot's book.