the reason why they made the threats public is because, in order to intensify Fed's security, they decided that his training sessions would not be in public and that he would not sign autographs. Nobody would have understood if they had done that without saying why, and there would have been rumours anyway.
Sorry to say so, but in my opinion, the security should be allowed to send off fans at practice events and anywhere else, without any reason given, if they feel so - and perhaps most often, because Fed - or any other top player - actually ASKED them to do so.
You are over-reacting.
I've been at quite a few tournaments, and whenever Federer, or anyone else, asks for his practice sessions to be held in private, fans should acknowledge that. And fortunately, most of times, they did.
In fact, in case a player doesn't want to appear in public, doesn't want to hand out autographs - he doesn't need to, there is NO OBLIGATION to do so, with or without an explanation to the 'fans'. For whatever a reason or no.
And well, I'm glad that Fed's security has the priority in the Chinese's eyes rather than autographs. In European countries in such a case, I think he would have been much less safe (Rosset said last week that if anybody wanted to kill a player, it was easy to do, and what happened in RG 2009 final if not Seles' case proved it in my eyes).
And I can't help but to think that you happen to exaggerate said 'death threat' too much to think about.
Come on! Like other people have already posted - celebrities, ANY ONE of them, get these kinds of threats all the time
! That's just one of the many nasty things one has to deal with when being a celebrity, and Fed is one of them, oh yes... and rightly so.
The best thing to do is NOT to give any attention to these kind of disturbances, let the TPTB deal with it, and that's all to say to it, and be done with it.