Tax Cuts and Consequences

In an opinion piece, the New York Times decries the Bush tax cuts and takes the liberty to make a capricious interpretation of the Constitution, specifically Article I, Section 8, and wastes no time in doing so.

The very first sentence of the opinion piece reads, "The tax system in the United States is supposed to mitigate inequality."

This is insane. I have not been able to find anywhere in the Constitution the phrase, "mitigate inequality." (Nor will you. They are not there.) Certainly not in Article I of the Constitution ,which establishes Congress's taxing authority, do these words appear; nor in the 16th Amendment, which gives Congress the authority to tax income, do these words appear.

Whose Constitution are they looking at?