What is real banana? How much processing is allowed for it to be still real? Considering the selective breeding of banana, is banana even still real?

Chemical is just a bad word choice. Artificial, or ultra processed get closer to the issue. They still are vague with a lot of grey area. If you cook at home, you're also highly processing your food. The fruit in winter is likely also artificial, in some sense: Grown against the will of god/nature with pesticides, in a tent, in a climate that doesn't naturally feature them, devoid of flavour because they were artificially bred for yield, color and size, etc.