Quick answer to one question: yes, these elements so occur in some foods grown organically, but a big chunk of the problem is man-made. Example: even organic strawberries and kiwi have a high level of salicylates.
The goal is not to eliminate all salicylates, sulfites , and amines (would be imposssible as there is a small amount of at least one of these in many fruits and veggies naturally), but to avoid getting too much of them - and you can do that if you know which foods to avoid.