Call me old fashioned if you will but...
I take pride in my work. Of course it helps that I'm a geek, but I enjoy working within IT, tinkering with stuff, network administration, sorting stuff out, keeping servers running, etc, etc. Sure, losing your job isn't fun nor easy, I speak from personal experience as well. Happened quite a few years ago, but I still remember.
But seriously... No matter how mad I might have become I'd never stoop so low as to violate the trust people placed in you like that. And it's also something I don't get to be honest. If you're a real sysadmin (at least in the way I vision it of course) you'd think twice before taking such a destructive route. I mean, seriously, trying to destroy the very thing you worked so hard to build? That part makes no sense to me, none what so ever.
Not to mention that there are much better ways to fight such a thing. Legal ways that is. Unless of course you're under a contract which expired and wasn't renewed. But especially then it also was something you could have seen coming, or at least kept in mind as a possibility.
But... "let's put the blame on everyone else except yourself". Seems to be a very modern thing these days and to be honest it often appalls me.