I often go until late afternoon or longer without realizing I haven't had any water to drink. This really doesn't seem that bad. The OP's claim that his mouth was like sandpaper because he hadn't had water for a few hours reads like hyperbole to me.
N.B.: I'm not pulling out a strawman, or claiming you agree in any way with what Rumsfeld did. I'm just pointing out that your logic could, and actually does, lead to such inhumane practices. So don't be too hasty to dismiss stuff like this just based on your personal experience and preferences. I'd personally die without drinking ample amount of water (not an illness; just habit, and it would make me really, really nervous and angry if you denied me water).
There is very little consideration in this thread for the shittiness and stressfulness of the TSA jobs, especially when faced with passengers who refuse the scan and set off the bomb detectors. If you want to argue that TSA should employ highly skilled workers and pay them better, I'm all for that. But given that's not the case, workers being incompetent and rude to people who set off bomb detectors, and holding them too long, doesn't seem like human rights violation to me. It's just a crappy and annoying and stressful situation.