No longer a dragon slayer

Why cant pantheon solo dragon at lvl 1, 2, or and 3. That was the perfect thing that made him a dragon slayer. It was the only reason i got him and now its pointless. I tried to kill drag in a bot game since it has been a long time since i used him then i saw my passive ain't do shit. So did riot think that was to OP? Pantheon passive says "After attacking or casting spells 4 times, Pantheon will block the next incoming basic attack or turret attack." If you die by dragon it says it was a basic attack that killed you. So why is his passive not blocking it anymore? Its almost like he does not deserve the dragon slayer skin, ALMOST.

P.S talk about a mistake, block the next basic attack but does not block the dragon basic attack XD. Down vote if yall like XD.