Re. the "security reasons" argument... surely if you want to shoot down a plane even the silliest terrorist wannabe would think of just sort of hanging around with his RPG somewhere along the LOC path?
Similar noises are sometimes made by people regarding the AIS system. As an AIS user in my professional life, those sites with live feeds have come in handy a couple of times in situations which would have necessitated escalating were it not for the ability to see beyond our own AIS range that those sites provide.
Scaremongers, politicians, and impressionable people might have a different opinion.