Responding to the original queston in its most basic sense.
Since a fruit’s purpose is to disperse seeds to propagate more plants and since Humans don’t defecate in areas where the seeds can grow - it makes a lot of sense to me that nature would not want fruit to be eaten by humans.
Before we developed agriculture, only an eyeblink ago in evolutionary terms, there were many millions of years when we did in fact defecate where the seeds could grow - and this is why the fruits evolved features to make them attractive to humans. (Actually, many fruits probably evolved these features to make them attractive to other animal dispersers, but they happen to be attractive to us as well.)
Since agriculture, of course, natural selection on the plants is irrelevant, because we are practicing artificial selection on them.
Ripe fruits in general lack toxic compounds, because they “want” animals to eat them and disperse the seeds. (Some may have compounds that repulse one kind of disperser while not a more appropriate, for example chilis. Birds can’t sense capsaicin and disperse the seeds, while mammals can and, except for humans, leave them alone.)
Seeds on the other hand often contain toxic chemicals (e.g. apple seeds), because the plant does not “want” an animal to chew and digest them, but instead pass them through the digestive tract intact.
That’s if the parents take the kid to a doctor. Does anyone know how many purported peanut allergies are diagnosed by a doctor, compared to how many are amateurly diagnosed by the individual or parents?