Just going to address a few points here in case people believe this!

> plant-eaters are less healthy because they have a less diverse diet The idea that herbivores have a "less diverse" diet is rubbish. Lots of herbivores (like elephants or deer) eat hundreds of different plant species.

> "ruminants, or woefully unsuccessful" This is also rubbish. Horses, Rhinos, Elephants, and Rabbits are all highly successful non-ruminants.

Oh and the reason horses can die from too much is because they have a one-way digestive valve, so if they eat something toxic/gas-producing, they can suffer from colic, which can be fatal. Saying they only lived "a year or two" is pure speculation btw and they aren't "fragile" because of evolution, they are "fragile" because humans have bred them for extreme speed and aesthetics, at the cost of general health etc.

I don't know where you get your information from, but it all seems very biased or hyperbolic to fit a certain viewpoint.