I'm not 100% sure where I stand on the safe temperature threshold for racing. I think this cold snap a lot of our Midwest to Northeast tracks are under is pretty perilously close, if not over, the line for safe racing.
But let's assume no track - right now - is subjecting horses to abuse racing in this weather.
If so, the Meadowlands' cancellation looks like a cop-out. Meadows went today; Mohawk is currently racing; and as other have pointed out, Yonkers raced.