Earlier quoted context omitted.
What if someone knew your password and requested it to be deleted? Wouldn't you be "Why can't they just not delete it after a period of days?"?
Ah, the old security vs freedom debate. I would know whom to blame if I had used a weak password that got cracked in order to delete my account. And I think you should expect the same from every reasonable adult. But yeah, FB should add a stronger auth for that dialog - more than a password and a captcha field.
FYI: Facebook is not primarily populated by reasonable adults.