Fair point about the source, but the classification usually follows the mode of delivery, not the organism of origin.

Many plant-derived compounds function as venoms once introduced into the bloodstream (arrow coatings, darts, etc.), even if they’re also toxic when ingested. Curare is one example of a plant-based compound - lethal in blood, but largely harmless if eaten.

So while Boophone is absolutely a poison in the ecological sense, using it on arrows still fits the venom/toxin distinction better than a purely ingested poison. Otherwise why would people hunt with this if they got sick the second they ate the meat?