Joseph,
Let’s review. The Agudah originally released a statement encouraging people to attend the rally. The majority of Gedolim on the Moetzes did not sign-on with their colleagues who later forbade going. None of those who signed that letter have been accepted by the entire Klal as “Posek America”. Unless one’s personal Da’as Torah is one of those against going, there was no reason not to attend and thousands correctly did so.
Live your life the way you always have and feel free to make up your own religion. For the rest of us, things aren’t automatically forbidden unless specifically stated as such by those in authority to do so.