You are missing the point entirely, which is that Apple should be apolitical. Their message should be about their product, not about their politics.
Why should Apple be apolitical? Apple, as any other privately held company, should be what its owners - i.e. its voting shareholders - want it to be. Shareholders express such desires by voting for the board, and the board places a guy in charge who is the spokesperson for the company. If the guy in charge voices a particular opinion in his role as a CEO, then he's speaking for the company, and ultimately, for the shareholders. Do you expect the shareholders to be utterly apolitical?
Furthermore, the political view that is voiced is not even necessarily matched by the shareholders, but they can expect the company to voice it for the sake of PR. Given the stereotypical Apple customer, this seems like a smart strategy. Then there are employees, who do expect a some degree of political alignment from the companies they work for - and, again, given the overall IT culture in US, and especially in the Silicon Valley, being firmly pro-gay-rights provides Apple with a good public image from hiring perspective.
If you don't like it, why, go ahead and voice your displeasure by selling your AAPL stock. If enough people will do it, the company will notice. You have the shares, right? If not, then why are you even bitching about this in the first place?
Because slandering an entire state is not a positive message.
It's a positive message insofar as it works toward reducing discrimination. Or at least most of Apple's customers will see it that way, which is what matters. And "slandering" is, of course, just your subjective politicized twist.