To clear up a lot of confusion I hear.....
One can believe that the birth of the state is an act of G-d, that it is part of the redemption process, that it was miraculous, that it is a great improvement over what was going on before, love Israel etc. etc. without celebrating Yom Ha-atzmaut. Creating a new holiday in the 20th century without Ruach Hakodesh is a very novel concept.
Again - if you want to celebrate then ENJOY!! Have me in mind. But I hear even intelligent people who assume that if one believes in the G-d of Israel then he or she MUST celebrate the fifth [some years the sixth, this year the seventh] of Iyar. Otherwise the person is a scoffer and denier.
I am not sure about that....