Oh no, I completely agree that you don't nerf a champion when you obviously walk into their win condition, it's just that people like to blame things on others when there was nothing they could do.
People will say "MF did no damage that fight," because Yasuo put up a wall. Yeah, she cast R and got off 3 waves before Yasuo walled it, saw the wall, stopped it, and tried to get an angle to help but couldn't because the enemy top laner was too close for her to walk through the wall. So instead she walks back and gets blamed for "no damage" when her frontline dies.
In that case, MF's frontline needs to kite back with her, cause she can't help them where they are until the wall goes down. Instead, they just stay in the fight and blame. Without the whole team knowing you need to kite, people will do the same thing over and over and blame it on Yasuo's wall as OP. Yeah, it has counterplay, but a lot of it requires the whole team to know how to counterplay it, not just the MF in this case. Yeah, she probably shouldn't ult until he uses his wall, but that's a different story.