Impeachment Trials of Presidents must be presided over by the Chief Justice. The Chief Justice is not presiding over this "trial", therefore it is not an impeachment of a President.
But if the "trial" is not impeaching Trump as a President then who is it impeaching? If it is impeaching Trump as a private citizen then that is technically impossible, and becomes a Bill of Attainder, which is explicitly unconstitutional.
(post is archived)