Not to put too fine a point on it, but Peter Vlaming is well within his First Amendment rights in referring to a "trans-boy" in the objective case as "her," even though he'd already agreed to call her by a masculine first name,

Because he's already known her for a couple of years as a girl, and because when he looks at her he still sees  her as a girl. And that's all that matters. It does not matter that his Catholic education has taught him that it would be a sin for him to deny the evidence of his senses. All that matters is that he might not wish to do so

Because, you see, there is no such thing as transgender. At all. Really.