Lame point - with Twitter and Facebook fans of every artists have a voice. I once received death threats via Twitter from Bieber fans because I said he was rubbish. There was no Facebook/Twitter 20 years ago in 93.
Weren't there bulletin boards or something?
Anyone threats can be in a physical form letters, parcels even people turning up at the door....because it wasn't publicised doesn't mean some nasty things didn't happen.
It was publicised a reporter who broke the 1993 case was immediately harassed by MJ fans.