I can't agree with him because of what the Bible says. Curiously, we became rancorous about applying the second half of the Ten Commandments, but it's the first commandment that makes sense of everything that follows: "I am the Lord your God, who brought you out of the land of Egypt, out of the house of bondage."
Thanksgiving is a time to thank God by reaffirming -- not just in theory, but in experience -- he and the Bible have proved worthy of our trust. At the times we feel let down, we still know -- because we have learned through hard experience -- God is the only source of light. Even the bleakest of the 150 psalms, Psalm 88, recognizes that.
If our deliverer sometimes asks us to affirm certain tenets that cause us difficulty or surpass our understanding, we should do so because of the relationship he established with us, one that causes us to say not "thank," but "thank you." In the end, we give thanks not because God has given us a lot of food (or a little), but because he changed our hearts.