Why are rematches unrated?


Rematches, on their own won't be unrated unless the original game was.
In my experience that's not the case. I play almost exclusively rated games, but every time someone challenges me to a rematch, it's for an unrated game. I've noticed that when I challenge someone to a rematch, it defaults to unrated also, but (if I recall correctly) there's option to change to rated.