>>5923
>I still have a bare idea of it despite reading

>>5918
>I can't be sure if that is do to some reason that would make sense later

*due, not do. Also, motive, not motif. Insert grammarnazicat here.

So, the "back cover copy" IE description on fimfic would give this away:
The premise that spurred this particular combination, was the tale "Code: Majeste" in which a lady ponified as alicorn, and it came up that the pony technicians had standing orders to destroy (kill in their sleep) anyone who came through as an alicorn.
WHY would Celestia feel so threatened by a one-in-10,000 random chance? What made them that uncontrollable?
In this AU(and AU to CB standards) there is, at least, a pretense to reason. The appearance of a caste system is real, and is enforced externally. Earth ponies can't help but do the will of unicorns, and even pegasi terrify and awe the lowly earth pony. And of course, regardless of intelligence or aspirations, alicorns seem like small gods to even the haughty unicorns.
With that revealed, let me give you the title of this piece:

Magic is Friendship