Presumably Amazon, Facebook and Google are using RC4 for speed reasons, though it's not really thought to be secure anymore.
RC4 is fine in SSL/TLS. Nobody likes it, but until relatively recently, the AES ciphersuites were all CBC mode, which means they burned a couple bytes of padding for every record. RC4 is also faster than AES, which was, until very recently, an issue for server performance. We have AES-CTR ciphersuites now, but I'm not sure how widely deployed they are.
Well, Matt did write something wrong. The original post about nginx "sucking" at SSL was wrong. Maybe it sucks for SSL in its default configuration (is that even that case, or was Matt's config copy/pasted from elsewhere?), but saying it sucks in general is incorrect and link-bait'y. You can presumably configure other web servers to suck just as much at SSL by enabling DHE ciphers and providing DH params.
We're commenting on this blog post . As was Ben, who didn't comment on the previous post, but did single this one out here and, as I recall, on Twitter.
It sounds like you're implying that when someone posts something on the internet, when you're evaluating the usefulness of that information, you should ignore anything else they wrote previously. Frankly I don't care all that much about Ben's motivations behind calling out the author here, but I read both blog posts as they came out, and the lack of attention to detail in the first post definitely affected my opinion of the second post. I don't think a lack of participation in the first HN discussion means you're disqualified from participating in the second one using information from the first.