[TJR]

I can't understand what sort of assholes would enjoy raising somebody's hopes, and crashing it down on them, and doing it publicly.

Supposedly, Yamanaka has a history of picking on that seiyuu (among others), so this wasn't exactly a harmless prank that was pulled out of the blue.

Hajime Kikuchi's comments may be egotistical and disgusting, but they sum up the heart of the matter (and are probably shared by countless others who haven't been vocal about it). It's an ugly culture that's perpetuated by people in all sorts of positions, whether they're producers, animators, or seiyuu.

Have they issued an official public apology? Is there a chance that might help to quench public anger?

It's tough because the prank was initiated from the top-down. Even if they were to throw a couple seiyuu under the bus (and yes, the tendency would be to blame a scapegoat and then downplay or deny personal involvement. The idea is to redirect or focus public anger on people who are expendable), it's well known that Starchild's producer, Silver Link's president, and various staff of both companies were behind the stunt.

An apology isn't possible without powerful players admitting guilt and taking responsibility, which would hardly help the two companies.

Because she's rumoured to be producer Yamanaka's favourite (or in 2ch's own words: his slut). She apparently gets frequently casted in his shows and he retweets her on twitter and etc. That's roughly the gist of what I managed to find.

By "favourite", it's a snide suggestion that she sleeps with Yamanaka for roles (in terms of timing, she landed a major role in Toradora! after nearly a year during which no one in the industry would cast her).

Unfortunately, this kind of arrangement happens, so speculation always arises whenever a female VA becomes favoured by a producer/sound director/agency head and enjoys a quick rise to stardom.

Obviously, there's no proof of any wrongdoing, and it's a case of guilt by association. Nevertheless, otaku love to run wild with this stuff.