Tobacco companies expect you to lose years of your life, tens of thousands of dollars and return you yellowing teeth and nails, smelling bad and lessened taste and smell. Evil.
WoW expects your monthly subscription fee and you'll probably put some time into it as well. They don't actually care how MUCH time you put into it, just that you're engaged enough to keep playing. In return they give you fun, a sense of achievement, a vibrant community and new content. Not Evil
Zynga games are boring. In fact they're worse, they're work. They guilt you into playing, they try to manipulate you into harassing your friends, they're designed to nickle-and-dime and get you playing as much as possible. In return you might get a sense of achievement, but you irritate your friends and waste a bunch of time on a game that isn't any fun. Evil.
I think it's always evil to engineer a product to be addictive. Compelling yes, addictive no. If you don't return a positive benefit to the user then even compelling is evil.