Why is that so? Clicked your link and saw that this manga had just 29 chapters.
I don't know it yet but was it so bad?
Remembering Mx0 I can see it had its flaws but was one of the better manga … well poor guy I guess.
Kagami isn't that bad, it was decent at best. It still entertained me once in a while.
And it seems that Kagami wasn't canceled (just like what others believe with Mx0), it was Kano that stops doing his thing. I read someone say that in the cover flap of Kagami's first volume, Kano said that he messed up the foundation of the series etc. and got cynical. So I think the main problem was him.