Sure, it's not '48 laws of harmony and cooperation'; I think it's a legitimate authorial technique to challenge the reader and push them out of their comfort zone - and yet the book is abundant with examples of how greed and hubris can lead to a sticky end. The book seems to generate strong reactions in a lot of people, both those like yourself who say it's evil and from others who say it's too wishy-washy (one hard-charging person I mentioned it to derided it as '48 laws of brown-nosing'). I wonder if you have read the whole thing? If not, why not borrow it from the library, saving yourself the emotional conflict over whether to enrich the author, and give it a full read.
The fact is that it's a competitive world, and attempts to improve upon human nature often turn out to have serious negative consequences; apparently benign beliefs such as christianity can become vehicles of horrid repression. Better, then, to improve the world by securing for yourself the freedom to do so in peace than by wishing away the facts of life.
The biggest lesson I got from this type of thinking is that people are surprisingly predictable. I don't know where to draw the line between recognizing behavioral cues and patterns and manipulating people but at the least being aware of the potential should help you avoid being manipulated yourself.
(Of course, psychopathy/sociopathy is probably the closest thing to a medical description of "evil" that there is...)
Edit: Yes, I am suggesting that the 48 Laws of Power are inherently evil.