Look at which states those early primaries were in. Either Blue or at best purple. Only really Red state was South Carolina, where the black turnout was a very important component of the Dem turnout.
IOW, for the most part there were more Democratic votes because the primaries were in more liberal states. That was by design to help Hillary in the primaries, before they knew her opponent would be at least as liberal, a preferred minority, much younger and better looking.
Well, Iowa went for Bush as did S.C.
And in S.C. where the GOP race was hot and included McCain, Romney, Huckabee and Thompson, 530,332 Democrats voted compared to 428,075 Republicans in their respective primaries.
In 2004 in S.C. 937,974 voted for Bush and 661,699 voted for Kerry in the General Election.