UNIX is not hacker or vulnerability proof, neeither is Linux. The only system that can be hacker proof is one disconnected from the net. The security guys are not spreading fud. The only reason why UNIX wasnt cracked more in the 70's is becausethe Internet
Of course, Mac OS X based on Unix, Windows not. Linux is still safer than both. What I like is how the anti-virus guys trying to spread the FUD.