You know everything about why the Changelings invaded.

It wasn't because they're some violent race; it was because they were desperate. Love is a scarce resource and they need it more than ever. You won't let an entire species die out. You'll stop at nothing to help this species become prosperous.

Even disobey Princess Celestia's orders.

This is an Anon in Equestria story. If you do not enjoy having the main character's name as Anonymous and dislike second person perspective, please leave rather than complain about it in the comments.