Those both happened before the Internet became a common source of information for everyone, it would be a lot harder to demonize someone now that the mainstream media has competition.
And you have to admit, it wasn't exactly the hardest thing for the media to demonize Weaver and Koresh, since they were isolated from the public. If an individual or a group had an online presence and they appeared to be good people to the public, it would be next to impossible to wipe them out without a serious case of appearing to be the bad guys.
Also, this guy hasn't been taken out yet, why is that?
http://en.wikipedia.org/wiki/John_Joe_Gray