That's because The Rock as a deck is incredibly amorphous. It's practically an archetype unto itself. Anything more controllish than Eva Green and more aggressive than Train Wreck and optionally splashing any of the other colors could potentially be labeled The Rock. It's not even like Threshold where a base 20-30 spells are shared across all the variants -- you could probably come up with two separate lists which are both The Rock and which have zero spells in common* (though I haven't actually tried this).
* okay, maybe besides Tarmogoyf
And yeah, when combo is as powerful as it is in Legacy right now, you're not going to get too far against it when various one mana discard spells are the best disruption you have available. I think you'd have to either splash white for more/better hate or just suck it up.

