it seems that the guy is only a Rafa-fan who a guy who speaks a lot on Chinese forums, then I think it's reassuring : not the kind of person who would be brave/real enough to make such an act, especially in such a context as the Chinese police.
Besides, "Blue cat" posted a date : october 6, that is saturday, which means that after that we will be able to feel relaxed
"On October 6, I plan to assassinate Federer for the purpose of tennis extermination," read the message, posted under the name 'Blue Cat Polytheistic Religion Founder 07'
sounds like some MTF posts like Raferminator's
the Chinese police are cautious and will offer a high protection to Roger and they needed to explain it to the fans, that's all