I saw the play and would have ruled it a double as well. Obviously tough break for the pitcher. But the 2B tripped. Just one of those things. A little surprised that nobody else was around to help - the ball was in the air forever. The only thing that really surprised me was that the announcers were so flabbergasted by the scoring decision. And i usually support the announcers and enjoy listening to them.
Would have been a great to see the RF step in and make the play when the 2B fell down....I used it as a teaching moment at our last practice!!! Never assume anything and always backup the play, no matter how routine.
If the fielder is going back, that is considered extra effort so it is always a hit.