Problem is there has only been trust between three of the horde races and even that was put on quite the shaky grounds during mop. The horde is a pragmatic organization they are bound together through interests, not something like loyalty or cultural understanding.
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It is quite rare for someone to be raised again and usually requires incredible powerful necromancy, the forsaken for example don't have someone of that caliber. Even restoring undead is quite taxing for them.