Truly a horrible fate.

@Background Pony Number 17  
That’s Racist (joke)

Head-canon: Earth ponies consider themselves to be the only “real” ponies.

Hardly. It’s pretty well established that earth ponies have their own magic that pegasi and unicorns lack, so the others weren’t turned into earth ponies – they were still pegasi and unicorns, but unable to use either earth pony magic (because they weren’t earth ponies) or their own magic.
 
And on that note, theirs was hardly an unwarranted response to what was effectively mutilation. I’d like to how you’d react to somebody making off with your hands.

Oh that’s not fair. Pegasai stripped of their wings or Unicorns without horns don’t get the many advantages Earth ponies innately have.

well it is when you are not actually an earth pony and they don’t have supah strength

Ah this old chestnut.
 
They do get the short straw though don’t they?