Still fairly new to the game, but request clarification

I know that this is gonna make me sound like the newbie I am, but I dont understand how Master Yi is a healthy champion from a design point

In my match history, there is a Malphite game that I lost. I thought I did fairly well and built my character optimally. I was 5-0 at one point and I successfully killed my lane opponent 1v1 twice and killed the Yi in his jungle when I fought him at his red.

But he buys rageblade, presses R and kills me in 5 seconds. I had more levels, items, gold, farm, kills, a Sunfire, a completed Thornmail, Ninja Tabi, and glacial shroud. He had a Rageblade. Zero kills. Not much farm. Zero impact on the game. And I'm playing a champion that seems like it's designed specifically to counter melee and champs.

It'd be different if I got outplayed. But he just autoed me to death. This is kinda how is always been I guess