goes out of bounds as well?
The defensive team didn't recover the ball and earn the possession. That is why and that is why they shouldn't get it when it goes through the endzone.
The last person who has possession should get the ball. Now if the defender gets the ball and refumbles it and it goes out of the endzone, than the defensive team should get the ball.
The rule should be: whoever last possesses the ball when there is a fumble and it goes out of bounds or through the endzone, the last person who had possession of the ball should keep it.