> Or perhaps plants are just as sentient as humans

The burden of proof is on you. Humans are animals. We have evolution linking us together at a more-recent junction than we do when compared to plants. Humans and animals have brains; brains is the seat of sentience.

Finally; even if you are right that plants are sentient, are you then claiming that there is no difference in the amount of sentience between humans, bees, and plants? If so, should we be indifferent whether I kill you or burn a dandelion?

No, it just means that sentience is a poor metric for determining whether we should eat something or not.

I think vegetarianism is about a whole lot more than sentience. I aspire to vegetarianism for energy reasons. It comes down to how many square meters of sunlight-on-chlorophyll is required to support a meat eater vs a vegetarian, vs how many are available.

But even if it were just about not wanting to kill things that resemble us--it still doesn't have to be a false elevation of human sentience.

If there are fungi that make decisions, I'd expect them to look out for their fungus-buddies more than they look out for me. If Jupiter's red spot can be asked, I'd expect that it cares more for the weird hexagon on the poles of Saturn than anything going on on earth. Seeking kinship with similar things and being indifferent to alien things is common in biology, and it gets along just fine without sentience in the mix.

I agree and I think your position is legitimate. My issue is just with those vegetarians who claim a universal moral superiority over meat eaters. This attitude is extremely prevalent, just reading the comments here. “No justification”, “no excuse”, on and on.

I think vegetarianism makes a ton of sense from an environmental and ecological point of view, but this has nothing to do with the moral one.

I think the focus on sentience is misplaced. Rather, the value should be rationality, meaning here the ability use one's mind to survive and to live by reason alone. This is valuable to any other rational living creature because rationality allows one to eschew violence and live cooperatively, so it is in the best interest of every rational creature to, at least on a basic level, value and respect the life of any other rational creature. The reason we don't apply and respect rights to animals and plants is because they are incapable of doing the same to us, or even being aware of the concept of 'rights'. You should interact with other forms of life on the highest level it is capable of interacting with you.