I was thinking that as well but tonight is -3 degrees in oldham so the pitch may have been frozen.

Also the path leading from the RRE down to the JR stand would have been dangerous, and oafc probably tried to second guess.
I remember a couple of years ago when they called off the boreham wood(i think) game about half an hour before the game. The away fans travelled for hours and were livid, and it was a total fiasco.