Who are you to decide who should be treated through the 'normal' legal process and who doesn't deserve to be? If these terrorists don't deserve it, you probably feel that a murderer doesn't deserve it either, or should we draw the line at a serial killer?
And are you absolutely sure that everyone detained is a terrorist, couldn't there be innocent people among them? On what you call the "battlefield" of this war, I assume you mean Afghanistan and Iraq, there are people living, who are no more a terrorist than you and I, still you see newsstories about innocents being picked up, who are suspected of involvement with terrorism.
But it has been proven in the recent past that every intelligence in the USA is good and perfect and therefore it is impossible that innocents would end up in these secret prisons, isn't it?
Btw if you treat them humanely, that does not mean that you cannot question your prisoners, there is no law that forbids that, torturing people, while questioning them, that is a whole other story.