People hate Young because at his best he is the player who will be MOTM vs Stoke, or will have decent game against City. He'll never play as great winger, he'll never impress you with his performance, at his best he is good squad player and that's it, and that "best" happens so rarely that people forget he can be a decent player. His style of play is unattractive, I can't remember when is the last time he tried to beat his defender, and apart one or two screamers per season he won't do anything else that will impress you. He has so negative mentality you just see he isn't player for top team. There was one game this season where his average position was almost identical to Evra's, and apparently he was winger in that game and Evra played as fullback. Apparently he is good at setpieces, but we scored around 2 goals after his deliveries from set pieces. They also said his crossing from open play is good, but most of his crosses from left would be too high even for Crouch who would be standing at back post. I remember us one time scoring after his cross, and that was probably overhit too, when Giggsy scored against Norwich. There was also one game when his every single completed pass was backpass. For some reason we play him ahead of more talebted players like Januzaj, Kagawa or Nani, only to sub bim after 50 minutes. His dives from past few seasons were embarassing as it gets(altough tbf looks like he cut that out of his game this season).
I don't think he is that bad player as some do, I think he can be good squad player, and he seems like a decent person in real life, but it's really not hard to see why people dislike him as a player.