The Princesses are immortal, but they are not gods. And they are not invincible. They may be alicorns, and their magic may be strong, but they have a good reason to have formed the royal guard. They can't protect themselves. And thus it is made true knowledge to everyone that this is the reality of the royal sisters. They are taken, and the kingdom threatened. Naturally, the royal guard react accordingly, as they had trained.

Naturally, the politics told them to stand down….