Master yi Q unable to be spell shielded mid cast?

Recently I played a game against a master yi and bought a to counter his Q with its active. But you can only cancel it if u use it before he uses his Q? You can't cancel it mid animation before the damage is actually dealt which just seems wrong... Like, I can spell shield vi while she's in mid ult or karthus so I feel like that move should work the same way... I also heard even if u use a spell shield before he casts his Q if he uses it on someone near u instead it will still do dmg to the player if hes in the strike... Idk, I feel like this should be changed?