Isn't he forgetting something

Eugene Volokh points to this quote by Dahlia Lathwick about the Defense of Marriage Amendment:

The political reality is even more compelling: A Defense of Marriage Amendment would enshrine, for the first time, language of intolerance and exclusion in a document that was intended to set forth basic rights. Does President Bush really want to be remembered as the guy who first used the Constitution to codify bigotry?

Eugene points out that this argument is entirely unconvincing because Bush and other who support the amendment clearly don't believe their view constitutes bigotry. This is an excellent point. There's something else though. Lithwick claims that this would be the first instance of bigotry being codified in the Constitution. Putting aside the angle brought up by Volokh, Lithwick seems to be forgetting a very part of American history. It was called the three fifths compromise. That and the Constitution's temporary protection of the slave trade in Article I, Section 9, Clause 1 would, I think, pretty clearly constitute a codification of bigotry.