I just had a game in which I had more played ranked games than my entire team combined...

Thank you matchmaking.

And a player with a total of THREE ranked games played ofc flames me for his mistakes. And toplane Riven instantly goes feed.

... this might the the first time I have been proud of afking a game. Why should I even bother? These guys stand absultely no chance to our enemies as they are total newbs. Why the hell am I grouped with that? Just why? Riot do you want me to intentionally lose games just so I can get them over with?

(Because this is how you climb: if game is lost, lose it quickly and jump instantly into the next game and try winning that instead of wasting a potential 30+ minutes on an obvious lost cause. "Never surrender" only works a) in bronze where people throw literally everything and b) above Plat where you can expect your team to not be actual shit. Between than, just drop a game if it goes bad. Way more efficient. )

I refuse to put effort and energy into truly pointless things, such as trying to carry a bunch of total noobs against veteran players.

Seriously, fix your matchmaking in this regard! This is not supposed to happen.