Being racist is morally wrong.
Okay. So the underlying cause you see as morally different, but the acts taken–refusing service to black customers/refusing to patronize a racist business–are morally equivalent, other than the racism?
Considering that Sherman Alexie grew up on the Spokane Reservation and has personal, first-hand experience with discrimination and its consequences, I completely understand why he cancelled and I support his decision to do so.
Although that doesn’t stop be from being bummed. I really wanted to go to that signing. 
The short answer is that NC attempted to discriminate against people based on their sex or gender, which violates federal law. Now whether you agree or not with the law isn’t the issue. It simply provides a context why it is not allowed for the florist/baker to do what they did but allows Pearl Jam to do what they did. The florist/baker wanted to discriminate against a protected class. Pearl Jam wanted to make a political statement. Only one is protected and that is why there’s a difference
I don’t know how the law treats a specific church so I can’t respond to that. But if you opened a public business providing services to people, but then decided you don’t want to provide services to Christians, or blacks, or women, then you should not be able to have that right. If you wanted to privately solicit non-blacks, or non-Christians, and do taxes for those people, I think, but I’m not sure, that wouldn’t count as a public business and you can do that
I skimmed over this the first time I read Pearl Jam’s statement, but it says they will be donating to local organizations. I found more information on their website, which lists Equality NC, the LGBT Center of Raleigh, the North Carolina NAACP (which is protesting HB2), and a group called QORDS (Google has a “may be hacked” warning for their website so I didn’t click on it, but it seems to be some sort of LGBT youth group) as organizations they are supporting. There’s also a link to the Equality NC petition to overturn HB2 with a request for fans to sign it.
It probably would have been better for the band had they turned the show into a benefit instead of canceling it – they’ve now disappointed several thousand of their own fans, some of whom must have also lost money on travel arrangements – but I’m not sure it would have been better in terms of getting things done. Canceling the show likely attracted more attention to the issue than turning it into a benefit (would we be having a thread about a benefit concert?), North Carolina is losing out on whatever money the band, their crew, and out-of-state fans would have spent locally, and it may be that Pearl Jam is donating as much as they could have raised with one benefit concert anyway.
I’ve been having this argument with one of my co-workers ever since Bruce Springsteen cancelled his concert. Her position is that this is hurting the people who depend on this business, like people working at hotels and restaurants and convention centers.
I said, “Yes. And you know what those people are called? Voters. Every one of these businesses and bands that are cancelling are making it very clear why they’re doing it.”
She responded, “But that’s hurting people who didn’t vote for McCrory as well! Why should they (meaning we, since we both hate the [vile profanity deleted]) be punished as well?”
At this point I realized there’s no arguing with her on this, so I just said “We’ve been punished for the last four years just with him being in office,” and moved on to something else.