I have nothing against Iran joining the Mecca alliance, in fact I welcome any initiative that brings Muslims closer together and creates a new geopolitical reality that could challenge Israeli hegemony in the Middle East.
Gathering together as Muslims is a divine command and it is the only thing that makes us strong in the long run.
However, this comes with important caveats; What is the true nature of this alliance, what guarantees will be given, and does it really benefit Iran or is it just there on paper? Important matters, such as the war between Yemen and Saudi Arabia, need to be resolved before any such alliance can happen.