Not quite, actually... In terms of production methods, yes, being vegetarian IS indeed more Eco friendly... but at the same time it is not. And there is also a reason why the meat "normal omnivorous humans" DO consume largely is from herbivorous/omnivorous animals, and it's not just because of the extra nutrients obtained through it. (even if we only receive 10% of what they received, thus only 1% of the photosynthetic energy the plants received from the sun.)
It's, ulteriorly, a way to keep a type of check/balance. If we suddenly stopped consuming meat, even if we could still obtain a healthy amount of nutrients from such a lifestyle, it would be a terrible decision when you look at the ecosystem developmentally. We are now what keeps a lot of herbivorous species in check... Livestock more specifically. (even if we are also the reason they're on the verge of ballooning out of control in the first place...) If we suddenly stopped killing them for food, and let them produce at will, even if another animal started to pick them off, it wouldn't be at as rapid a pace, thus the population of these creatures would swell out of control... and thus an overconsumption of plants would occur, causing their lifespans and growth patterns to shift dramatically.
If I need to back up this argument, allow me to go off topic with my basis. Wolves. In Yellowstone more specifically.
Basically, If humanity all decided to go vegetarian due to just being more Eco friendly with production methods, we would be essentially exhausting the world's resources faster than nature could recover from. It would bring about mass conflict over who controls the more rapidly dwindling resources and how to portion it "fairly" (though the past has shown that is never the case...) which would, of course, spiral further out of control.
So, I think what I'm trying to say here is, as good of an idea as it is, we are currently in a spot where the omnivore population has to considerably outnumber the herbivore/vegetarian population of humanity to keep a type of check or balance in order.
Believe it or not, I actually agree to an extent, Live. It's just AP Bio has taught me to really nitpick these types of things. I just couldn't keep the "flaws"/missed details I spotted to myself.
Though I may just be looking too far into it again... I always find an argument at 1 AM.