To be FAIR, his campaign is to "give the TONYS back to BROADWAY." He doesn't say he has issue with Hollywood stars being on Broadway. I interpret his "mission statement," if you will, to promote the desire to have BROADWAY host, present, and perform on the TONYS.
Now, Sean Hayes, Catherine Zeta-Jones, and Scarlett Johanson are making their Broadway debuts, so it was very much justified for them to be there. I don't really get Hunter Foster's point...other than Green Day.
"The Spectacle has, indeed, an emotional attraction of its own, but, of all the parts, it is the least artistic, and connected least with the art of poetry. For the power of Tragedy, we may be sure, is felt even apart from representation and actors. Besides, the production of spectacular effects depends more on the art of the stage machinist than on that of the poet."
--Aristotle