If you get accepted into US universities with your high school then obviously it meets the requirements. Now...
Think about it logically. There are 55000 DV visas technically available each year. They need a standard, you can't expect COs around the world to be trying to figure out each and every case on its own merits especially when education systems differ everywhere. There are some countries where their "bachelors" is only equivalent to a US associate degree for example, and where (at the university i attended) they would have needed a master's to apply for a master's - as it was only seen as equivalent to a bachelors - and all linked back to their high school system falling short of equivalency. Again this was not DV but academic entry,but you see the point. So something may seem obvious to you, less so to the people trying to set a standard that COs around the world dealing with tens of thousands of visas can apply without spending a day analyzing each applicant....
Also perhaps it doesn't apply to your country, but many countries have a mature age exemption or accept equivalency for college entry - neither of which count for DV. So it is not at all obvious that just because you attended college you finished high school. Also not to be rude, I'm sure yours is different, but in my country it used to be that "teachers colleges" which have a four year diploma were only attended by those whose grades were not good enough for university entrance. So again,nothing obvious, especially when you consider that a fair amount of people interview In countries that are not the same as where they went to school.