Why the hell can I not deny this follower?

I am (as a Dwarf Shaman) supposed to help out the Grimtotem so they can hold their own against the Legion (and also ultimately the Alliance, said in the dialogue)

Also, she killed Cairne...

I mean, okey cool, nice character... But at least allow me to deny her!

She is demeaning in every questline and she pretty much hates the alliance... Still, me as an Alliance character am supposed to help her out so she can grace me with her help against the Legion?

I am aware this is not the time for petty fights... But come on... She essentially is the cause of everything that happened in MoP and WoD since Cairne would have defeaten Garrosh...

Cheers, Sorrol