He's right about what they mean in Knights of the Old Republic, but that's far from anything canon and done for gameplay purposes. About two levels after getting your lightsaber, you can pick up crystals that change the color to whatever you want anyway.
So, outside of the game...lightsaber color is pretty much meaningless in terms of power or advantage. The focusing crystals determine the color of the blade. The crystals often originate from different locations on different planets, so colors vary.
The only exception is the red blade, but even that's a bit iffy. Most of it is derived from very old Jedi lore. It is rumored that a perfectly honed red blade can, under the right circumstances, overload the inclision matrix of another lightsaber...thereby causing it to shut down and "breaking the blade". It is also thought (though not proven) that the particular crystals that produce red blades exist on a frequency that is attuned more to the Dark Side of the Force. Thus, while anyone can build a red blade, only a Dark Side user can make it perform to its potential, ie: breaking blades.
This is, of course, conjecture. Recent discoveries about the nature of the Force bring this explanation into dispute. Many Jedi historians believe that the crystals required for a red blade were only found in the area of space that the first Dark Jedi colonized after the Jedi Civil War, thus founding the first Sith Empire. After that, it just became tradition, or a "sign of the Sith" sort of thing.