[Question] Azir, his soldiers and his autoatacks

Riot stated that soldier's "autoattacks" are considered spells, so items like rylai's and liandry's may work. But not autoattacks, so if you buy nashor's, the soldiers will not deal extra damage from nashor's passive.

I get that. Perfect. But why, WHY, if you attack an enemy champion in lane with your soldiers, you draw aggro from minions? Weren't supposed Azir soldier's autoattacks to be considered as spells? (when you hit someone with a spell, you don't aggro minions).

This drives me crazy pre-6 when minions hit as hard as teemo, and it's ilogical since the soldier's AA are considered spells in-game, so there should be no reason to draw aggro from the minions. I would like to know Riot's PoV on this since I have never seen this addressed on any other place not even talked.