Okay guys let me explain before you start to trash talk...
Lets assume there is a game where one team is comprised of average players who are able to communicate and are decently organizing teamfights. The other team has let's say two good players, two bad players and one troll/feeder.
So the game starts, because even if you know about the troll in champ select you still can't do anything about it without being penalized. Let's say that good players are midlaner and ad carry, while bad players are jungle and top and troll is support. We will be looking on the game which has lower chance to win and thats the team with troll.
So top is slightly loosing, mid is slightly winning, while bot is being pushed due to the troll, who feeds. AD carry in the best case can maange to hold the lane before jungler arrives, but since jungler is the bad player, he doesnt or he fk's up the gang. Meanwhile enemy jungler starts babysitting mid so that the only lane that was winning so far is checkmated by the second team.
And now Riot's logic: You are going to punish ALL the players BECAUSE they played the game which they in such sitiuation COULDN'T win. What exactly are you taking LP points from ad carry and mid? Because they were both basically fighting 2v1 lanes?
If there was no penalization for early surrender in rankeds OR it would penalize you only with negative score (which would be of course have to be calculating both kills and assists ratio with death ratio), while the winning team would still get the score, then what's the problem?. If ALL five or four players agree in 15 minutes that the game is lost, then it probably means it actually is LOST. People dont early surrender just like that, they surrender because something goes seriously wrong. Heck, even LCS surrender when the opponents have few more kills. Do you think they lost LP because of that?