You are correct and the other poster is wrong. The reason that game makers include the type of processor in their minimum requirements is because, as you have noted, it's very important! The 2.26 Ghz Pentium M processor in my notebook is more powerful than a 2.6 Ghz Pentium 4, and of course your processor can wipe the floor with mine.
What matters for the game is how much data the processor can deal with in a certain amount of time, not just how fast the clock speed. Since your processor can deal with at least twice the data per clock cycle per core as a P4 CPU, that would mean you'd need to have around a 1.3 Ghz CPU if it was only a single core. However, your processor is dual-core and Starcraft 2 recognizes and can use dual-core processors, so that takes the number down by half again. Essentially, the minimum dual-core clock speed for your processor type to play the game is roughly 700 Mhz, and since you have a higher clock speed than that in dual-core and a higher clock speed than 1.3 Ghz in single-core, your CPU should have no trouble whatsoever playing the game.