If 87% of people who consume porn became rapists, I would be concerned. The other way around is irrelevant. They could say that 87% of rapists eat Coco Puffs and it wouldn’t mean a thing.
Perhaps acts of lust are created in the mind, ala Jimmy Carter, and not all are physically acted out.
I suppose some dots could be connected if, along with the statistic cited, there were other studies showing a rise in the statistics involving sex crimes and the rise in the amount/availability of porn.
In and of itself correlation does not prove causation, but that is a trite observation.
One can't help but notice that the easy availability of porn and the rise in frequency of sexual crimes are highly correlated.
But even a casual examination of the porn industry itself readily reveals the damage it causes to its participants.