The Shado-Pan failed in their duties given by the Celestials BEFORE the Horde/Alliance appeared on Pandaria. The Celestials had managed to trap 3 of the Sha. The Sha of Fear, Violence, and... Hatred?
The first to escape was the Sha of Fear. Because of the Shado-Pan's failure, it escaped, and managed to infect the Empress of the Mantid. This had to have happened months before we arrived, because there are comments about the odd Mantid activity in Jade Forest.
The Sha of Violence escaped later, but chose to Fester in the Shado-Pan Monastery, hence the change in the Shado-Pan throughout the questing experience.
The Sha of Hatred escaped through Suna Sunstrike, and disappeared. Her death from not being willing to let go of her hate for Taran Zhu led to Taran Zhu blaming himself for what happened to her, and hating himself, allowing the Sha to have the power to overcome him when he returned to the Temple.
The Shado-Pan are the fault for most of this. The ONLY thing the Alliance/Horde are at fault for is the Sha of Doubt that they broke the Celestial's Seal on in the Jade Forest. And even then, that was mostly the Hozen/Jinyu. Everything else was the fault of the Shado-Pan for failing in their duty. That is why they accepted the help when Taran Zhu became possessed, and why Taran Zhu accepted help in dealing with the Sha of Anger and Fear.
It's all cleverly written to make it look like it's all the Alliance/Horde fault, but it's not.
As for the actual topic, people need to grow up. Your warchief ordered the goblins to destroy a sacred Vale that you had to make an oath to PROTECT. Of course they're going to kick you out. The Pandaren are not Alliance or Horde allies. We are guests on Pandaria. Nothing more.