Why do abilities with on-hit ignore the basic rule of spellblade?
Spellbalde items:

Spellblade causes your NEXT basic attack to deal bonus damage AFTER using an ability (1.5 second cooldown). Wiki
Next basic attack. After using an ability.
No where does it even hint to on-hit abilities counting as the "next" basic attack. This passive clearly requires an ability to activate and then 1 basic attack to proc it. So why do some abilities ignore this? It is a basic attack on-hit, not an ability on hit.