Ryan McAvoy said:
As I've said I suspect Card knew what it meant on some level. However, I'll concede that he may just have been using it in the Harry Potter way you mention, like "Damn", "Bloomin'" or "Bloody". For example if he'd done a series of books about wars with Vampires, his characters might have dubbed "Those bloody Vampires!" as "Blooders".
I honestly think that much is pretty clear. It was a pejorative term, but not a reference to sexuality. Bugger was not capitalized as a proper name, though Formic was. Clearly it was slang, and meant to be insulting. As you pointed out, he began to emphasize Formic later, possibly to avoid any connotation with the archaic term.
Interestingly, later in the series another sentient alien species is discovered. They are given the proper name of Pequeninos, Portuguese for little children. But they are nicknamed "piggies" (with a lowercase p) because of their pig-like snouts. I doubt Card was making any statement about overweight people, or people with upturned noses, or perhaps little Portuguese fat kids.
And @CP3S, stop being a boob (by which I obviously mean you are a female anatomical body part) ;) I'm not in denial over the meaning of the term despite my prior ignorance, but I find it impossible that anyone who has actually read Ender's Game would believe Card's intent was such. The original story is over 30 years old, and it never became an issue till recently (since Card has made several statements on the topic in recent years). As you say, educate yourself my good fellow, and read the book ;)