You failed to demonstrate any good faith so this is the end of this conversation. Your reply reveals that you even understand that you were wrong (“it’s designed that way”; “the language changed”) but are so prideful, so averse to ceding ground, that you just… can’t… say it!

I’m not sure you have enough theory of mind to understand what that’s like for a normal interlocutor, unfortunately.

The children you really ought to stop teaching are more mature than this. You’re an embarrassment to the profession.