The issue is that this person or company created a 'copy' of a particular string of code and enprisoned it within the users RAM, disallowing it from functioning properly. ... The problem was, this program created a "copy" of said code within the RAM, circumventing its intended purpose.
There is nothing wrong with having a copy of any program in your RAM as long as "such copy or adaptation is created as an essential step in the utilization of the computer program."
This 'hack' was obviously not an essential step, and Blizzard was therefore able to sue.
Under that ruling, it means programs can only be loaded in ram as designed by the writers of it. This makes it illegal to do things like have a user load up entire programs into ram to increase performance (example: When you have load times for a game, it's because you're transferring stuff from HD to ram usually, imagine if there was a 3rd party program that could pre-fetch and entire game into ram, you'd need like over 8gb of ram for this to work with a modern game, but it would still be an awesome thing to do).
Blizzard wasn't able to sue because the hack wasn't an essential step, otherwise anyone could sue any 3rd party program for any program. Blizzard was able to sue for an additional copy into ram that the software wasn't designed to do. Loading up software to ram outside of the normal is very useful. Look up vista's feature that pre-loads stuff to ram based on what it thinks you'll be using for an example, this ruling might make -that- illegal depending on exactly what vista does, but I doubt you could ever win a lawsuit against microsoft on this issue, it's likely just overturn the original ruling.
Also it's important to realize, WoW is -not- a game in terms of law, it is a piece of software, a ruling on how WoW's software works, is a ruling on how windows, microsoft office, your tax software, everything can be used. Now no 3rd pt programs can load parts of another program to ram to do something without being ready to fight this decision in court should they be sued. Imagine a 3rd pt program that duplicated your web browser's session (I know firefox already has similar built-in features, but easiest example I could think of), so if it detected a crash, it'd open a new copy load up the session and kill the old copy in under a second, causing minimal interference from a crash. That'd be pretty useful no? Hardly a hack that deserves being sued for copyright infringement.
Bottom line: Copyright law is to prevent against bootlegging, brand dilution, and stealing profits, if you use copyright law to fight against
anything but this, you're abusing the law. Indirect lawsuits are pure bullshit and make things worse for everyone by making legit things in certain conditions illegal under all conditions.
P.S. There's nothing inherently wrong about making bots, cracking programs, and etc... There's a reason why you can't sue bot makers for making bots, it's the same reason you can sue gun makers for making guns. It's the use of a tool that's wrong, not the creation or possession of one. You could argue there's no "good" use of a WoW/ffxi specific bot, but the law doesn't work in specifics, a ruling against a game-bot is a ruling against a bot that automatically spiders the internet (i.e. googlebot).