It was not because of all the offensive rebounds that the Raptors gave up.
Yes they gave up a lot of second chance points
But lets look a little bit into the simple box score
The Hornets scored on 85 points on 87 shots. Any time you hold your opponent to under 1 point per FGA for the entire game you should win.
The worst scoring team, the Bucks averages 1.14 points per FGA
The best scoring team, the Knicks averages 1.29 poins per FGA
So for the game the Raptors did a very good job in holding the Hornets to under 1.00 point per FGA.
The Raptors took only 74 FGAs compared to the Hornets 87 FGAs and the Raptors made only 13 or 20 Free throws.
Yes it is true that if the Hornets had not gotten so many second chance points they would have scored less.
However the Hornets who are the best defensive team in the NBA based upon the fewest points allowed per game give up 1.18 points per FGA. The Raptors managed only 1.09 points per FGA vs them. The Hornets also give up an average of 78 FGAs per game yet the Raptors managed only 74 FGAs attempt them.
The Raptors lost the game because they turned the ball over six more times than the Hornets thereby giving the Hornets six free as it were extra possessions. The Raptors also did not make their free throws 13 of 20 and made only 2 of 13 three point attempts both abysmal shooting percentages for those two categories.
On the road the general rule is that you need to not turn the ball over and make your free throws in order to win. Both of which the Raptors did not do.