Genuine question: why?

Oh, this is good to know! I haven't encountered this issue personally yet, but maybe once I've updated my mailserver, I won't encounter it in the future.

Now to figure out how to stop the same thing happening in SMS.

It's crazy to me that a decision to buy your own gTLD would even be approved outside the most rich and tech literate companies. The evaluation fee alone is $185,000 USD and you have to pay quarterly fees too if I'm not mistaken.