I'm not sure your comparison of fast break points and offensive rebounds helps a lot for the reason you bring up. It's true that "just because you rank high in offensive rebounds doesn't mean you give up a lot of fast break points" but its also true that a measure of the effect of offensive rebounds cannot be ascertained by looking at a blunt measure like total fast break points given up - For as you point out, lots of other things can lead to fast break points. In some ways its just common sense, it you are sending guys to the boards, they had better be very fast to get back if they don't get it and given the speed of players today, it may be too late even if they are. I think my basic point is still true - most of the best teams do not emphasis offensive rebounding for fear of what it does on the defensive end. This was gospel 5 years ago. Coaches like Pop were almost religiously anti-offensive rebounding and the numbers of offensive rebounds league wide plummeted for years. There has been some analytical pushback on that position recently, but just looking at the teams that are excelling at offensive rebounding this year, there doesn't seem to be a positive correlation between offensive rebounds and wins.I don't know about that. Looking at the link you provided and comparing it to the same website's numbers for fast break points allowed per game, it shows that Oklahoma City allows the fewest fast break points per game but they are 8th in offensive rebounding. The Knicks are 3rd in offensive rebounding but have allowed the 4th fewest fast break points. The Suns are 5th in offensive rebounding but have allowed the 7th fewest fast break points.
Just because you rank high in offensive rebounds doesn't mean you give up a lot of fast break points. Charlotte is 9th in offensive rebounds and has allowed the 3rd fewest fast break points.
On the other end of the spectrum, Philadelphia is 28th in offensive rebounding but they also rank 28th in fast break points allowed. I don't think there's that strong a correlation between offensive rebounding and fast break points allowed. A lot of fast breaks come off turnovers and have nothing to do with missed shots. You also see fast breaks off missed layup attempts where the shooter ends up on the floor and out of bounds under the basket while the defending team grabs the rebound and has a 5-on-4 opportunity.