Yasuo doesn't counter you because he has the passive shield, he counters you because you're completely reliant through harassing him with autoes (nid spears are too easy to dodge and he out trades your cougar form because tornado), and Yasuo with LS quints and two Dorans can just out sustain your autoes. He wins any sort of all in, because he has an actual combat ultimate, and also scales much better so passive farming isn't useful.
Yasuo beats mid laners who are reliant on easy to dodge skillshots, and have no utility to offer their team in case they lose the lane or go even. It's similar to Nasus. He will outscale you unless you have something to actually kill his back line or any way to help your own team.
The passive shield does help but generally by the tie you get the second Dorans (which can be like 5 minutes after laning), you're fucked in the lane anyways, unless he's garbage.