I completely agree. The primary reason to not eat meat is that it's inherently unethical (factory farm or not). But a lot of people don't feel that way, so any argument that will persuade them to eat less (or no) meat works in my book.

I understand that view too, but insincere arguments have some drawbacks too. I do know some people who became disillusioned after hearing bad motivated reasoning on that, and on dubious health claims.

My current thinking is that both the eco and health questions are extremely complex. The moral issue, however, is simple.

Sigh... please explain why it’s immoral to consume other organisms?

It's immoral to kill a conscious and sentient life form for luxury, recreation, or other purposes that aren't absolutely vital to immediate survival. Eating the result is generally encouraging the killing. Of course that doesn't apply to eating an organism that died through other means, or eating synthetic meat.

The eating itself is neutral. It is immoral to pay people to raise other organisms in confinement and later slaughter them.

Crap my garden!

Your garden is fine. But he's going to judge you silently if he sees you near a grocery store.