tofu is good if it's been prepared well
I have no idea what you'd do if you had the stomach flu and you couldn't work meat back into your diet, afaik a lot of the protein-rich vegetables also have the thick shells that are hard on the intestines or are difficult to digest for other reasons like peanuts
I think that some of the economic / sustainability arguments are worth paying attention to though.
the few arguments I've seen have been very one-sided. they seem to fall back upon "plants = green, good for the environment" a lot, but of course that's not really the case. crop farming has likely done more damage to the environment and destroyed more native ecosystems than anything else. it's good propaganda, for the lack of a better term, to get people to rally behind bison or yellow-shouldered blackbirds, animals people can personify. but when it comes to more abstract things like ecosystems or plant species no one gives a shit. I do think that nowadays we've got the ability to promote the smart growth of farmland, but I question our willingness to rally behind such a dry concept