I know I only buy Card books used now.  I support my local booksellers plenty...

Card left the hate group and basically said "Gay marriage is legal now, I lost, I hope I can have some of that empathy you guys talked about."

But the poor dear is being picked on because people aren't being tolerant of his intolerance.

It's classic victim mentality. They can't accept that they're in the wrong, so they believe they're persecuted.

I have no idea about the rhetoric, but that's a GREAT point I never thought of before.  It's not just Ender, either... Alvin Maker is extremely empathic as well... maybe you have to be a little crazy to be a great writer.

As an ex-Mormon I may have some insights into that. Warning: if any Mormons are reading please tell me if I go too far, and I will edit this to be more gentle. If the mods think this is too much for a comics board feel free to delete this post, I won't be offended. I tend to take things seriously and write a lot, which does not always fit the tone of the board.

OK, short answer: Orson Card is a devout Mormon, and the church has become more hard line during his lifetime.

Long answer:
The Mormon church is all-encompassing: it provides your entire social life, world view, your closest relationships, etc. So devout Mormons toe the Mormon line. (Here I use "Mormon" as shorthand for the Utah church: I actually self identify as a cultural Mormon, but not a Utah Mormon - that's a whole other topic). Card published Enders Game in 1985, and it was a different world. Since then the church has changed and Card changed with it.

While nobody could ever call Mormonism liberal, it was once more relaxed than it is today. Mormons once believed that science would prove them right, so they were open to new ideas. While there were plenty of extreme right wing Mormonsthere were also liberal Mormons: it was a broad church.

Two things happened around 1970 that changed that. First, two men with rigid views gained power: the young-earther Joseph Fielding Smith became church president, and the powerful speaker and bold writer Bruce R. McConkie gained great influence. They opposed liberal views. Second, in 1969 (IIRC) the original documents to the Book of Abraham (a Mormon scripture) were discovered, and it was realised that the Mormon scripture was not what it claimed. For the first time there was a very clear and obvious example of science not supporting the church. the leaders became intellectually defensive. A church that had once encouraged (or at least allowed) speculative views now opposed them. A program called "correlation" gained increasing power, centralising authority to the fifteen men at the top and removing all altenative discourse.

When I was a child at church in the early 1970s we sang about snowmen and played games. But my own children in the 1990s had to sit quietly and sing a monotonous dirge called "follow the prophet, follow the prophet, follow the prophet, he knows the way"

What has 1970 to do with 1985? You have to remember that the Mormon church is like a supertanker: it cannot turn quickly. Every member is taught that he church never changes, so when it does change (and it changes constantly) it is through subtle changes in emphasis. It takes a generation for change to bed in. The leaders in the 1970s and 1980s learned their doctrine in the 1960s, when science was your friend, and it was OK to think differently. The leaders in the 1990s and later were raised in an ear when science was the enemy and obedience is the "first law of heaven". By 1993 Boyd K Packer (a prominent leader in the church) could openly declare that intellectuals were enemies of the church. That same year six prominent intellectuals were excommunicated. 

So when Orson Card wrote Enders Game in the early 1980s it was still OK to be open minded. But by the 1990s he had to decide: support the church leaders and become more hard line, or leave the church, or somehow compromise. Compromise is very hard in the modern Mormon church. Even today (11th June 2014) it was announced that two intellectuals who tried to reform the church are likely to be excommunicated. John Dehlin campaigned for gays in the church to receive more understanding, and Kate Kelly campaigned for women to have equal rights with men. There is no place for those messages in the modern church. 

Of course it is true that Mormonism has always been anti-gay, but in the past almost nobody spoke about it. It just wasn't an issue, the church seldom mentioned it and so the members did not feel the need to take a stand. but over recent years the church has chosen gay marriage as a topic to campaign on. Millions have spent spent opposing gay marriage legislation (mainly through highly organised astroturfing and quiet donations). The church leaders are now highly visible as anti gay, and so the devout members (those who pay attention) are as well.

In short, Orson Scott Card is a devout Mormon and always has been. Over his lifetime his church changed, and so he changed with it.

Sorry for such a long reply, but you did ask.