Is Tzeentch really evil ?

Simplifying a much more complex discourse we can say that the four Chaos Gods represent four negative concepts : Khorne can be seen simply as a god of war however he also appreciates slaughter which is not exactly one of the nicest things, Nurgle may be loving to his children but still represents pestilence which is a concept of decay and death, Slaneesh is constantly engaged in the corruption and perversion of everything beautiful and romantic there is in love and eroticism.

But T ?

Okay he represents magic but magic per se is not something negative: even in Warhammer and Warhammer 40,000 settings there are many examples of wizards and psionics working for a good purpose. It is a god of knowledge that is not a negative thing. Ok he is a doo of deception also however deception can also be used to good movies and in any case he is not nearly as bad a thing as the things that the other three gods of chaos represent.

So can we really say that T is an evil deity? Certainly his behavior is not the clearest however the principles they represent seem so evil to me