I had a game where I was mid 6/0/2 at 15 minutes with my bot lane BOTH 0/10/0 or thereabouts. (They ended, cumulative, 0/28/3, they fed enemy Ashe together until she came to shit on us with 24/1/2, and her only death was from JG)
Jungler was doing pretty bad, but not horribly.
Top was fucking off, idk, sucking his own dick or something, he was also doing pretty bad.
I didn't give up, I just surrendered when the vote came, but guess what? Bot lane refused to quit despite straight feeding, so we had to hold this stupid war of attrition where Ashe just 2-3 hit all my allies and I was the only one who got kills except the jungler.
We lost, obviously, but despite my team being hot wet garbage and me telling them so, I didn't get in trouble because I didn't quit/afk. even if the match is a dumpster fire, it's on you to keep trying, even if you're just half-assing it. You don't have to play seriously, but you do have to play, otherwise it's on you for going afk/quitting. That's counted in the reports, "Negative Attitude: Griefing, Giving up, etc" as well as "AFK/Leaving" so imo they were right to report you.
I would have, and if I ever hard afk for a match or give up, I fully expect my team to report me for it.