Once a statement becomes an object of derision mere reason and logic in defense of it become pointless. The mob will hoot down the reasoned statement of fact. The mob will think itself intelligent and sophisticated for doing so.
It is unusual for men to assume women's names. Sorry. It is a fact. Expressing surprise is not unusual in such a circumstance.
No amount of hooting or derision can change that. It is common to express surprise when a man assumes a woman's name.