I see your point, but it doesn't make sense logically. Most certainly nobody should be able to claim they were the SOLE reason that their team won, although they can be a huge reason for it. Someone can do EVERY SINGLE THING RIGHT, and still lose a game. Therefore the loss would not be their fault.
Winning doesn't mean you got carried though. It means enough people did enough work to get it done. You can still be the primary reason that your team won.
I know this is a bot game, so it wasn't as hard to "carry" the game, but the concept is the same:
http://matchhistory.na.leagueoflegends.com/en/#match-details/NA1/2452225899/236778104?tab=overview
Without me, the game would have been lost. Period. However, without the Varus, the game probably would have been lost as well. So while I was not solely responsible for the win, I was actually the primary reason we won. We almost lost, and it wouldn't have been my fault, because I was doing everything I could (I am not going to say I played perfectly, but I didn't make a single major mistake).
I got First Blood about 2 minutes into the game, although I did end up dying a couple minutes later in a 1v2 matchup because I was getting minion blocked. A small mistake, yes, but not major. I got a double-kill around 5:45 and then Varus came top to help me push the tower. We killed both top laners two more times and took the top turret pre-10 minutes. By this point bot was getting pushed in hard and mid was dying left and right. At 10 minutes into the game I was 5/1/1. My Varus was 2/0/1. The rest of my team was a combined 0/6/0 and had already lost bot tower. I picked up another double-kill at around 11:30 and then rotated mid to help Kat who had just destroyed a tower. We took the inner turret mid, and then there was a small skirmish in mid-lane which resulted in two kills and three deaths, as well as the enemy Ashe and Lux split-pushing to kill our bottom inner tower. Since I didn't think I could take mid-inhib tower faster than Lux and Ashe could take our bot-inhib tower, I backed and got a quick double-kill on Lux and Ashe. At this point, I'm sitting at 10/1/1 while the rest of my team is a total of 3/9/X (No idea how many assists they got off that skirmish). My team keeps trying to run things down the mid when there aren't enough people there to do so, or when people are too low to really fight and keep dying. I manage to get two "unofficial triple-kills" as well as the "unofficial Penta" at 33:00.
I "carried" the team, even if I didn't do 100% of the work. Saying I "got carried" because I won would be stupid, considering I did 43.4k damage to champs and the rest of my team combined for 45.1k damage to champs. I also had double the CS of anyone on my team. If I had been unable to 1v2 (And eventually 1v3 when WW kept going bot after the inner turret was down) the bot lane after my team let the enemy team take those towers, I don't think anyone would have been able to say it was my fault for losing the game, since I won my lane, hard, and roamed mid and helped push, and roamed bot to defend.
Now, I am not defending people who claim to "never be at fault" for a loss; most of the time they are making mistakes as well. But quite often a player can play very well and not make mistakes and still lose the game because their team folded on the other side of the map. That doesn't diminish their efforts in the loss, NOR does it diminish their efforts when they do win. There is a player "Saber is Waifu" who plays extremely well in almost all of their games, even the losses. Most of their losses are not their fault, their jungler goes 1/9/1 for example. That doesn't mean that all of their WINS are not due to their efforts (0/1/23 support, 14/2/12 top, 12/1/2/ top, 0/3/25 support, 4/0/7 top, 10/2/10 top, 12/0/1 top, 11/0/4 top, 16/0/8 top, etc)
