Because with all the comment-spam, the waiting-to-be-moderated comments list looks like a Chinese chat-room. I have yet to see any Hindi. And anyway I'm sure the machine producing the spam doesn't understand the symbols.
"...there is good and bad speculation, and this is not an unparalleled activity in science...Those scientists who have no taste for this sort of speculative enterprise will just have to stay in the trenches and do without it, while the rest of us risk embarrassing mistakes and have a lot of fun." - Dan Dennett