At the same time, animal feed is rather low quality and not classed as "fit for human consumption"; animals that eat grains would get the bits that aren't good enough for bread and cereal companies. I don't know what the Western standard is for human consumption and how much of it would be suitable to go to starving countries, just that dog food was originally put on the market as an economic use for grains and animal products that could not be sold to humans and would otherwise be put to waste. And that's man's best friend.The only argument for not eating meat I encountered which hold water (IMO) is that to rear animals we have to give them a lot of food which could feed more people than the meat will with environmetal implications etc.
I think the big thing (and maybe more specifically what you had in mind) is that the amount of land used purely for cattle grazing could instead be used for growing crops.
And, there is a point there, but if we were to count all the things we should go without so that resources can be put to better use, I'm not sure meat-eating would be the biggest waste
Also, I'm curious, what about the manner in which fish are caught do you find morally compromising? (Not being provocative, I genuinely know next to nothing about fishing, aside from what I learnt in Finding Nemo).