Did someone say you have to defend yourself? You just inserted yourself in the conversation and, following the usual reactionary rhetoric, made yourself a victim.

I don’t understand (some) people’s negative visceral reaction to vegan / plant diets.

My best guess is it’s the very small but very vocal minority who actively criticize meat eating.

The majority of vegans and vegetarians don’t really care whether other people eat meat. It’s a diet, not an ethical philosophy for a lot of people.

You seriously don't see the pattern? Sorry to make you my outlet for this rant: It's the same reactionary (as in, anti-'liberal') response to everything; it's the same pattern, rhetoric, tone, etc etc. It's completely predictable; it's been going on for years. When will people stop playing this helpless role, to play it safe, to avoid confronting the obvious, overwhelming problem?

They don't give a crap about veganism; they just are following the reactionary playbook.

You don’t have to defend yourself for being born an omnivore. You just have to defend the ethical choices you make and the consequences of those choices.

Here's my ethical defense of eating meat.

Everyone and every thing dies, and in the larger scheme of things it matters not one bit. I'll make peace agreements with others where I see a benefit, and if I can trust that the other sees enough benefit to hold up his end of the bargain. Other than that, I see no reason to not participate fully in the full range of barbaric behavior the universe allows. Don't blame the player, blame the game. There is no referee who watches over to pass judgement either way.

“I will do barbaric things so long as there are no adverse consequences to me personally” is not really an ethical defence of eating meat.

Yes it is. It's just not ethics you agree with. But that's the great thing with ethics, everyone gets to pick their own. There's no right or wrong, just opinions.