Debuffs and Skills that are supposed to remove them

just wondering why some debuffs(feoh fear for example) cannot be removed by unbind/disparition/gravity barrier. all those skills mentioned above are supposed to remove all debuffs. is there any rule that makes some debuffs not affected by skills like unbind?

 

unbind you cannot do while with fear and disparition has chance.

 

it's another chinese fail... they just can't do everything right...

 

disparition : "cancels all your debuffs. for 5 seconds, you cannot be targeted".

where the hell did you see something like a chance ? :/