The sap was banned for much the same reason.
There are some alternatives on the horizon or on the market now. Sticky Foam is one that’s been tried but for a couple reasons it has not caught on with US police forces: https://en.wikipedia.org/wiki/Sticky_foam
"Problems with this technology include: the serious risk of smothering (suffocating) the subject; skin clean-up (the foam may not be toxic, but solvents are often harsh); "gun" clogging; targeting and firing; and gun cleaning."