Thanks for reading and leaving a comment. But, you're largely arguing against things that I haven't even said, because I didn't say anything about veganism. And, I wasn't even arguing against the idea of speciesism or the ethical treatment of animals (I have been involved in animal and environmental advocacy for decades — and note that I also discussed other ethical theories that can also reach similar conclusions to Singer). Also, I didn't suggest that plants are sentient. I suggested that sentience is a metric that is largely unmeasurable due to it being impossible to know what the conscious experience is like for another entity.

I really think you've missed the point of the entire essay. The main point is that using sentience as a boundary of moral concern is choosing an arbitrary metric where humans and other creatures that are like us are the clear winners. So, rather than most ethical systems, which are anthropocentric, it's simply changing to an ethical system that is zoocentric — and only a matter of degree less problematic than the previous anthropocentric ones. And, I personally prefer more holistic approaches to ethics.