At this point, I don’t really see a reason to assume that there’s something else going on. To me, this mostly feels like the usual discussion around natural versus synthetic psychedelics. Psychedelics strongly influence perception, so expectation effects and self-suggestion aren’t hard to imagine at all. Given that, it’s not surprising that people believe natural and synthetic versions feel different.
From a scientific point of view, though, there isn’t much to argue about. The only way a difference would really make sense is if there’s something else in the toad venom that actually contributes to the experience. I haven’t looked deeply enough into its full composition to say for sure whether there are other psychoactive compounds present in meaningful amounts.
So my advice would be to read up on what’s actually in the toad venom and check whether there are other known psychoactives in there. If there are, then sure, those could color the experience. But if not, I think most of the perceived difference comes down to expectation, context, and self-suggestion.
Another thing to take into consideration is the impact of collecting toad venom itself. Harvesting venom harms the toads and is already contributing to population decline, which is obviously a serious problem. This is especially hard to justify when a synthetic variant exists that is just as effective and just as impressive as the toad-derived version. Using the synthetic option avoids unnecessary harm, reduces environmental impact, and helps protect the species from further decline or even extinction.