Here's why people who play yasuo are usually feeding

Yasuo is a very strong champion with very good combos and very good passive skill. He is extra strong early game . and people play cocky because they think they can outplay 1v3 anyone with yasuo ... and that results them to get ganked , or make bad plays because they underestimate their opponent .

It's not the first time i saw someone play 1v1 on level 1 because yasuo has his Q on 1.75 sec. and die.
But even getting the kill where's that is going to lead? your opponent will tell his jungler "hey, gank top often because this guy play very offensive"

Not everyone is arkadata , and even arkadata if you noticed from his youtube channel plays extra safe early-mid game , until he has a lot of farm to buy items , and then he starts to push and carry his team .

Personally i am teemo-Lissandra main. and most of times my opponent gets a yasuo top he will play extra aggresive and he will use his E while near my tower and dive me , and he will die like a minion .

If you notice korean high elo players, don't play aggreive , they focus 90% on farm and warding . and when they are ready to do damage on the opponent they try with the help of the jungler to take kills/towers .