Let's discuss a bit of logic, shall we?
You are not special, and here is why!
Riot has not picked a special place for you, where you are in ranked is determined by your MMR. What this means is that every player around that MMR will be roughly the same skill.
Let's assume you are (kinda) special and you are actually way better than your MMR. This means that you are not a feeder. 10 Players play in a game of league of legends. Assuming that you are the only good player then 9 are feeders. Therefor you will have a huge advantage, as your team will have 4 feeders while the other team will have 5! You just need to be the one who gets fed, and if you are way above your MMR this should not be an issue.
League is a game that is too multifaceted to be determined by KDA, or "feeding" vs "not feeding". What role(s) were you playing? If you were ahead did you try to pass on your advantage to any of the other lanes? If you are better than your MMR, how did someone out carry you? Could you have warded for your other lanes? Could you have set up a gank or counter gank? Did you get global objectives using your power to bring back your team from a bad lanning phase? Did you communicate what the team should do to stay in the game, or just flame the "feeders"?
Remember that often times, feeding is a team activity.