But I'd say the plant response is still a simpler mechanism than an animals flight or fight response, with many animals actually having a complex nervous system to choose a response and to actually be able to perform the (I'd say) more complicated response. Like for a plant, if it senses any damage, it would probably respond in the same fashion for the most part for all damage done, whereas lots of animals when damaged will consider many factors and their variance, like the amount of damage, the mode of damage, and how much danger it is still in (at least we can infer from how they respond to variances in the parameters), which will subsequently change its potentially complex response (like place foot here, balance, activate muscle fibers to move in a particular chosen direction, avoid obstacles, etc), which itself could be highly varying. I'd say this complexity in an animal's decision making makes it more likely that animals have feelings compared to plants, which while they may send out signals similar to ours in response to damage, they dont seem to be complex enough to make varying decisions based on those signals (which in animals would probably be interpreted as feelings).