Denver Post Comment Section

I would also speculate that while Trump has been formally charged, he has not been officially “found guilty” yet.

That's the point of invoking the 14th though, it doesn't require a guilty verdict. It was originally used against ranking members of the confederates to prevent them from holding office even though very few of them were ever convicted. Specifically section 3:

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.