I mean I know who he is and read one of his books. In any case you should talk about him regardless of how well known you think he is because again, that's kind of the job of the OP. I'm not picking on you, I'd love to discuss him; but I'm not going to read a bunch of links to get up to speed.
What has he done that merits apparently-universal disgust?
I met him, back in October of 1983 or so. I wasn't impressed.
I went to a lot of science fiction conventions in the '80s and '90s, and had the opportunity to meet a fair number of authors. But this one stands out not for his writing (which frankly isn't that good), but for RL circumstances regarding that weekend.
I was in college at that time, and taking sociology... and frantically wondering what to do about my term paper, which was due not long after Thanksgiving weekend (Canadian Thanksgiving is the second Monday of October). The instructor, who had also been my Educational Psychology prof a couple of years before and with whom I'd already had arguments about science fiction (he couldn't wrap his mind around the concept of IDIC), asked if I was going to the convention in Calgary that weekend. I said yes, and he said, "Why don't you write your term paper about science fiction? Orson Scott Card is the Guest of Honor, and he's my _____" (I don't remember if he said OSC was his nephew or cousin, but my instructor was Dr. Brigham Young Card - I've mentioned him a time or two here, since he called me into his office and started proselityzing, wanting me to read a bunch of books on Mormonism since it really bothered him to have an atheist student).
So I went to the convention, met him, he autographed a book for me (
The Worthing Chronicle; I think I still have it around somewhere), and I remember wondering what I'd say to my instructor the following week if he asked my opinion of his relative. Thankfully the question never came up.
I found enough other things to enjoy about the convention, and on Monday I wrote that term paper mostly off the top of my head. Of course a lot of it wouldn't apply to modern fandom, since there was no internet or online communities back then. If you wanted to communicate with someone across the country or internationally, you either had to write a physical snailmail letter or pay for very expensive long-distance charges.
I've tried other OSC fiction; his Old Testament novels are horribly written. They're dull, repetitious, and on reflection that repetitiveness reminds me a lot of Kevin J. Anderson's style. Never say something once if you can say it fifty more times, and it's not really anything that matters that much. Not that I drink, but if I'd had a drink for every time OSC said that Leah had "tender eyes" or described her as "tender-eyed", I'd have ended up with alcohol poisoning.
Anyway, OSC is no longer welcome on my bookshelves. I don't like him, and I think he's a mediocre writer at best.
Separating a writer's actual writing from the writer's own self is something that depends on the circumstances and how forgiving a reader can be. I got into an awful argument in A&E with someone who berated me for saying positive things about Marion Zimmer Bradley. My view of the situation is that it is a fact that she mentored many young fantasy writers, some of whom went on to have very good writing and publishing careers of their own (Mercedes Lackey is probably the best-known of MZB's protegees). I still enjoy MZB's novels, and as for the RL stuff... I've looked into it and have decided that there's not enough evidence to convince me that I should burn every copy of her books that I own, every copy of Darkover or other MZB settings written by other people that I own, or even the Darkover fanzines I own.
There are a couple of Star Trek pro authors who have been banned from my bookshelves because of their very rude behavior on TrekBBS. I don't appreciate an author arrogantly demanding to know what made me think I had the right to criticize his writing. As part of the paying public who forked over money for his books, that gives me every right.