Well, suppose you have a really good teammate who saved you from disablers throughout the game. He might have topped the FF chart. The score screen alone would make you think he was a bad player. Suppose you have a player new to higher difficulties still adjusting to positioning. He might walk in front of you consistently and you might top the FF chart. Does that mean you’re bad? Nah. Suppose you didn’t even notice the FF that much, especially with temp health, but you see someone got the FF at the end of the game, as someone always will. People will start abusing each other when they otherwise wouldn’t have.
Another example would be damage taken. Suppose you play unchained with a 40% health buff. You might consistently top the damage taken category without actually dying in game. Does that make you a bad player? Not really. Maybe you did in fact make some mistake and take otherwise easily avoidable damage. The score screen doesn’t tell you that. Suppose the Unchained use her ult a couple of times as a panic button to save a teammate or even the run, and somehow ends up getting most FF. Is that bad?
Everyone has heard the saying ‘context is everything’ and for good reason. Now these are just examples, naturally there are players who troll or don’t exercise due care, but you don’t need a score screen to show you that.