The Huck voters are largely politically tone deaf, they will not see their vote as helping McCain.
They can be as calculating as they want to be. As myopic as they want to be. They had no problem spouting that a vote for Thompson in South Carolina was a vote for McCain. In fact, that was the biggest message Huckabee put out in the final week (at least officially). So, in the end, it's ok to do whatever as long as "God's guy" gets in.