Presumably this was a design choice: "Ixoth" doesn't really sound like anything else, which means Siri is unlikely to confuse it with another name or command.

Yep, this exactly. I purchased the domain originally because I was going to write a roguelike game, but then I got an iPhone 4S :)

The name comes from a monster in Nethack, for the curious: http://nethack.wikia.com/wiki/Ixoth