Humans are largely human because we are terrible "one-trial learners." We twist the tiger's tail until it turns on us. We don't learn. We come back to twist the tiger's tail some more.
i'd more say it's just that there's always some other guy who goes "yeah well they twisted the tiger's tail but.. i haven't twisted the tiger's tail so maybe it'll be different for me?"
then fucking somehow the tiger only smacks him on the head while making a funny face, he finds this fucking hilarious and does it again, gets his friends to do it, and now you have a group of dudes ooking like chimps while getting progressively more concussed while everyone else watches on with weary expressions knowing that this is just going to be a thing some people do from now on..
In high doses capsacin can be an irritant and cause temporary gastrointestinal issues in dogs AND humans
It is also a neurotoxin (GLaDLY only short term effects)
The dosage required for children and dogs may be lower as they are smaller
source
It has not been found to be lethal even at high doses in dogs and is quickly eliminated from there system. Source: 1, 2
Still don't put your dog in pain (they can't tell you when it hurts) and the side effects of high dosage can be dangerous just like in humans.
Guinee pigs however are very sensitive they can have long term health effects and it can be lethal so dont feed your guinee pig chilli (capsicum is great tho). Also other small mammals like rats, mice and rabbits can easily have a lethal dose because they are so small.
But yea from my research it is no more toxic for dogs than it is to humans