out of curiosity, what alien allies are you talking about? 
  
I would doubt anyone who would say that the Sangheili are still allied with the humans.  And before anybody says anything about Thursday War (which I haven't read yet), or that's just Storm Covenant, think about how humans work for a moment. 
We were at war with a genocidal alien conglomerate which wants to wipe out all of humanity, suddenly after about thirty years or so, one faction decides to switch sides.  And then four years later a part of that faction decides to rejoin that conglomerate.  I would highly doubt that there is a single human in the galaxy that would be comfortable around an elite.