Part of it is just that Tryndamere isn't fun to play against (but fun to play as). It's really one of two extremes, either he stomps you or you stomp him.
Does the champ base on autoattacks?
Rageblade
They dont have AP scaling abilities?
Rageblade, cockmongler
You dont want to build Rageblade?
Eat a dick and build Rageblade
In the last month of pro players using tryn Rageblade has been built EXACTLY as many times as lich bane on tryn. ******* retard g5 players with no concept of builds