Yes this guy is complete asshole. It doesn't take a real lot of thought to realize this guy acted deliberately to sabotage his employer. The lawyer who filed the suit made a mistake in the verbiage of the suit but there really can be no doubt that the intention of this person was to destroy the company. It will be interesting to see how this plays out but in mind this is pretty the same type of behavior as a person taking a baseball bat to the property of the company. It was malicious, intentional and hateful. Sure the company treated him like a piece of trash but that does NOT give him the freedom to ruin the company. If he felt he was wrongly treated he should have sought legal counsel instead of acting like a three year old when somebody takes away his toy truck. I hope they find this guy guilty but I have a feeling he will walk away thanks to the inept lawyer. Gosh this kind of sounds like HR creating the verbiage for a new hire posting.
Actually, the guy involved in this suit isn't the one who was let go from the company, he was hired by the guy who was let go (and it sounds like he was quite angry over the treatment of the first guy.)
But still, I don't see him winning this appeal and I do see this leading to some tightened up language in contracts for sysadmins. Because this was malicious at a minimum, which means you're talking malicious destruction of property (the backups, etc.) It's one thing to be told "you are responsible for our entire IT infrastructure, including cleaning up / removing backups / files / etc," and being told "take a baseball bat to our server racks if you want to." If you presume the first includes the second, you're very, very, very wrong.