Neither do the people who support him. If everyone understood the implications of what he was saying then they'd have walked out.
But people don't because people are uneducated. They don't think before they act and rallies like that are little more than managed mob scenes where group mentality takes over. The intelligent people who would honestly debate amongst themselves in their own living room leave their judgment at the meeting hall doors and will rah rah just about anything their candidate says. They don't resist the enthusiasm of the people around them.
Huckabee is not a fool, nor is he stupid. He's one of the many, many, people here in the US who believes that the US is the closest thing to God's moral force in the world. Listen to conservative talk radio or the Christian broadcasters. One of their mantras is that Christianity is under attack from forces both outside and inside the US. They instill in their listeners the idea that Christianity has always been the single force for US authority, not, "
We the people." Being uneducated in history, politics, and civics, these voters hear what they like and get caught-up in the mantra. They see TV which picks the most prurient stories, the most alarmist pundits, and their feelings of besiegement are validated. What they do not understand are the economic and social legislation enacted by both major parties which undermines not just conservative Christians, but all Americans. These people have no view of the world independent of what their chosen media outlets give them; media outlets controlled by backers of the status quo. The true politician knows that if you keep the people frightened, invoke God, and bait them with minor, tangential, but inflammatory stories, that the people will be more compliant. Frightened people don't think or act rationally.
The man is not even remotely qualified be President, if he doesn't understand or support the principles upon which your country was founded.