With all due respect, come on, it's separation of Church and State. The State cannot tell a faith-based organization what it ought to believe. Whether that agency is Muslim, Christian, Jewish, or of any other philosophical or religious persuasion (like PCUSA, which supports LGBT adoption), the state cannot tell an agency how it is supposed to feel about a tough issue like LGBT adoption. Of course a faith-based organization should not attack or slander LGBT people. Nor should it go out of its way to physically prevent them from living their lives as they please.
Members of the LGBT community have the right as per the First Amendment to organize and petition for their own adoption agencies. I believe we can all respect those of different beliefs than ourselves. If an LGBT nonprofit, for example, offers legal help or financial aid to LGBT people, and refuses to give that aid to a conservative Christian, that is their prerogative. They don't have to pay or work towards something they disagree with. In the same vein, LGBT and allied couples should understand that they cannot force someone to work for them if it is against that person's faith to give a child to be raised with exposure to a LGBT lifestyle. Everyone needs to respect everyone else's beliefs. Forcing faith-based agencies to give children to LGBT families is like forcing LGBT couples to start giving money to Westboro Baptist Church.
I am not a Catholic (or a Baptist), but here are some historical precedences pointed out by the VA Catholics: