No person shall be a Senator or Representative in Congress, or elector of President and Vice-President, or hold any office, civil or military, under the United States, or under any State, who, having previously taken an oath, as a member of Congress, or as an officer of the United States, or as a member of any State legislature, or as an executive or judicial officer of any State, to support the Constitution of the United States, shall have engaged in insurrection or rebellion against the same, or given aid or comfort to the enemies thereof. But Congress may by a vote of two-thirds of each House, remove such disability.
It's similar to the impeachment clause where the Senate can bar a convicted politician from holding future office. They didn't vote that all future convicted impeached cannot hold office.
Still, my point stands. Even if I were to accept the broadest interpretation that Congress voted to remove the punishment genetally, the language still exists in the amendment until the amendment is repealed or amended again. A future Congress can vote to reinstate the penalty if it wishes to.
That they have not done this is irrelevant; the fact that they can argues against the idea that the prior vote removes the penalty in perpetuity.
-PJ