There are issues that warrant debate outside of the realm of the Constitution, its case law, civil rights, and the relationship between the government and those governed – the Indiana measure is one of those issues.
Indeed, it was the Framers' intent to create a Constitutional Republic whose free and democratic society would allow for robust debate of the conflicts and controversies of the day absent the need for the government and courts to become involved.
With the above in mind:
The intent of the Indiana measure is to signal to gay Americans residing in the state that although you're now allowed to access marriage law, you are still unwelcome and rejected by most in the religious community of the state, and although the state must likewise be compelled to recognize your right to access marriage law in accordance with the Constitution, the state will offer no recourse or relief when you encounter discrimination in the private sector, as the state's official position is still that of one hostile to gay Americans.
The Indiana measure may be Constitutional and it may be valid, but it is otherwise wrong and reprehensible – and Americans across the country are exercising their right as private citizens, as authorized by a free and democratic society, to denounce the measure, call for boycotts, and acknowledge the fact that this measure is indeed wrong and reprehensible.