Jobs? Security? I don't think so.
As. For hackers using macs, its simple. They are lighter, have better screens and generally have the best battery life. That's all a hacker really cares about. If he wants to bootcamp he can, run linux? Sure!
Most hardcore it guys own macs purley because you can run the mac os easier than a hackintosh, and running everything else is easy as pie because linux and windows aren't picky about hardware like macs