Does Lee Sin really have tank shred?

Let's look at his Q first; the second activation is % missing HP.

% missing HP is an execute; you have to actually deal damage to the target first. If you have a giant tank with 5000 hp and you take out 1500 and use an ability dealing 10% of their missing health, the ability does 150 damage, which is 3% of their HP. A 2000 hp squishy who loses 1500 hp would also get damaged for 150, which is 7.5% of their HP. So if it deals the same damage (before resistances) to both squishies and tanks, it's not really %hp damage, is it? Unless you already have another ability/item that deals %current HP or %HP. Even then, you're still just amplifying the health shred that was applied before.

His ult deals %bonus HP, but only to enemies who collide with the champion he kicked. So if he kicks a tank, he won't actually be doing the %bonus HP damage to the tank. Kicking a Sion with 3000 bonus HP will deal 540 bonus damage to the other targets, which is a lot, but ultimately will still damage squishies and tanks for the same amount (before resistances).

Point is, Lee Sin does not have tank shred, he just has so much damage that it feels like tank shred.