Don’t forget that Warriors also have an AoE disorient.
Casters tend to have “sustainable” CC like Polymorph and Fear, but those require cast times. Versus things like Storm Bolt, Kidney Shot, etc that have either a cost or cooldown.
The problem isn’t really the fact that melee has CC, it’s just that interrupts are crippling to casters. Affliction warlocks especially are 100% reliant on Shadow school magic, so if any of their abilities are interrupted, they are out of everything for a while so it’s effectively another short-CD CC on them. Destro is a little better because if they get locked out casting Immolate, they can fear. If they get locked out casting fear, they can chaos bolt. Except if they are hit by another CC instead, then the cycle of being a punching bag continues.