Indigenous people get trotted put in defense against veganism all the time. The defense treats indigeneity like some kind of monolith, it's very off-putting.

Indigenous people in the US are vegan more often than white people, same with most BIPOC people. I would recommend asking a vegan indigenous person these questions, or even just imagine yourself doing so, and consider whether it comes across as stereotyping.

Anyways, vegans are generally not focused on going after indigenous diets. They're focused on the vast majority of people who consume animal products because they were simply socialized to do so and never had to question it growing up, but have no sacred attachment to their sloppy joes or slightly more durable shoes or whatever. It's just food or products consumed out of habit and folks pitch an absolute fit when you point out that, say, it's a contradiction to say you're an animal lover because you love your pets but you go absolutely apeshit on someone that asks you to not eat or otherwise consume (entirely as a luxury, a form of entertainment) pigs that are just as smart and cuddly.

Industrialized agriculture produces sufficient vegan food such that animal products are no longer necessary dietarily. Same for materials and other animal products. The question is whether it continues to be acceptable to harm animals because the products have entertainment value.

I think for most people the answer is pretty obviously no, but they reeeeaally don't want to self-crit, so they fight for a while first.