[Yes, it is pretty rude. Mettaton doesn't have to put up with this. In fact, he chooses not to!]

Well I can see that any well-mannered conversation will be getting nowhere with you, so rather than stoop to a level far below my own, I'll be going now~

[So saying, he turns on his heel and begins to walk, waving halfheartedly behind him.

Bye Felicia.]