Ethics may not be fully objective, but claiming that they’re fully based on emotion is a ridiculous thing to say. You can make ethical arguments based in reason. Pointing to the war and saying “see, ethics aren’t real” is an incredibly naïve conclusion to draw.

This is ignoring the fact that raising a cow for consumption requires ~10 times the amount of crops per calorie compared to just eating the crops directly. Also, I don’t think I’ve heard a single health expert recommend eating more beef - the universal understanding is that red meat consumption is generally a net negative in terms of overall health.