There's a lot of talk about how, well, things like the mortgage interest deduction, state and local tax deductions, and 401Ks contributions, are actually regressive because for various reasons most of the benefits go to higher income people. The extent to which this is true is being exaggerated a bit. It's true they don't go to poor people, but they aren't all just going to the top 5%. But in any case, the trade-off being discussed (and we shouldn't discuss these "bargains" anyway, as they're just a sucker's game for liberals) isn't, say, raise upper middle class taxes to give the money to poor people. The trade-off is raise upper middle class taxes to give all the money to SUPER SUPER SUPER RICH PEOPLE.
That doesn't make the tax code more progressive.