My eldest son doesn't eat meat. That includes fish & eggs. I don't remember about dairy products. Anyway, he's not preachy about it, but his quiet example makes me think periodically about the moral dimensions of eating animals, especially during Lent.
I generally assume that our existence, Creation, is the product of God's thought. God thinks the universe, so it is. So we all inhabit God's brain, to put it in physical human terms. And in the Beginning, there was no Sin, and things were in perfect harmony in God's head. But then there was the Fall, and Sin. Consider Sin as the opposite of God, yet existing within his head. Its effects wouldn't be confined to the individual sinner (as we know from practical experience); it could mess up, distort, warp, pervert any other aspects of Creation that it touched. Just to cut this short, St. Paul observed that the wages of Sin is Death, and any universe that includes me dying (dying? dying! ) is obviously screwed-up.
Anyway, back to eating meat, which is related to the Fall.
First notice how much meat Adam & Eve got to eat in the wonderful Garden:
In Genesis, God said,
"Behold, I have given you every herb-bearing seed, which is upon the face of all the earth, and every tree, in which is the fruit of a tree-yielding seed; to you it shall be for meat."
Apparently, dominion over animals didn't extend to eating them.
Later, after the Fall when Sin entered the world, Noah kept the animals alive during the Flood. When they left the Ark, God said,
"Every moving thing that liveth shall be meat for you; even as the green herb have I given you all things."
I suppose this is a sort of debt the animals owe to Noah: having saved the animals, and by extension all their descendants, Noah and his descendants are allowed to eat them....although this preceding passage doesn't make it sound like that's especially ok with God:
"And the fear of you and the dread of you shall be upon every beast of the earth, and upon every fowl of the air, upon all that moveth upon the earth, and upon all the fishes of the sea; into your hand are they delivered."
Which sounds awful. Yet in a sin-wrecked world God allows it. Apparently some things are conditionally tolerated by God after the Fall that would never have been acceptable in the Garden; which is hardly the same as saying they are good, or blessed, or even condoned.
Of course, we're allowed to still eat fish on Friday...but I regard the no-meat stricture as the Church's way to nudge us toward a Garden worldview instead of a post-Fall one.