3) When we eat a plant product such as potato, tomato, apple, pineapple, broccoli, etc, we are not eating the planet itself, but rather a 'fruit' or part of the plant that easily comes off. The rest of the plant keeps growing and produces more.
Since it is a conversation between you two I don't want to middle but I'll just reply to this since you are writing in bold, hmm wouldn't a similar analogy to the animal world, is to leave the animals on their own and eat everything they give birth for ? I mean if you take for example potatoes aren't potatoes the seed for future potato plants the same is giving birth to spread ?
Potatoes are not "intended" to be eaten. They are plant organs that store energy for new sprout after winter.