What I think is irrelevant.
While in general I agree with that, I am trying to focus in specifically on your comment that a business wouldn't be able to refuse service to the Jehovah's Witnesses. Not a specific witness, but the organization, the congregation (which is incorporated, usually) itself or the WTBS.
What I am driving at is what you think the difference is between a "customer" and a "person".
The State Attorney General said "Our law against discrimination prevents you from discriminating on the basis of race or religion or, since 2006, sexual orientation.
He's not illuminating that difference at all. I am asking YOU since you brought up the example.
Do you think discrimination based on some one's group identity is morally proper in some cases. If yes, which ones?
Well, first, the statement I was responding to was about discrimination in general, not specifically group identity discrimination. Obviously you can refuse service to an individual for a variety of reasons, choose who your friends are, etc..
For group identity, in general, yes. I think refusing service to people like, say, the Westboro baptist people is fine. Not because they are Christian or Baptist, but because I have a "no assholes" policy and by associating with that group, they've let me know they are assholes. And they are assholes.
Just like people that keep a Confederate battle flag on their car or house or clothes. That pretty much tells me all I need to know about that person, or someone with a Swastika.
OTOH, we do need to be careful in group identity. For example, I am considered very liberal where I live (SE US) and my friend is considered very conservative where she lives (Somerville, MA). The running joke is that, if we simply lived in different places and did nothing to change our value, our labels would immediately switch.