Native Americans killing and eating buffalos, doesn't justify eating meat

My reply to a person who brought up the Native Americans to justify eating meat:
Native American, or other people groups, ate and are eating animal products because of cultural indoctrination, following the eating habits of our ancestors and society.
That a group of people, or a society, has done something for thousands of years, does not in any way show whether something is morally right or not.
We all agree that “unnecessary” animal suffering and death are morally wrong. If that means anything at all, it must mean that we cannot justify animal suffering and death by reasons of pleasure or convenience. But what is our best justification for imposing suffering and death on the 58 billion animals (excluding fish) we eat annually?

Pleasure. Convenience.

So the only justification we have is that which we agree cannot suffice. This is moral schizophrenia.

Being a vegan is easy, better for your health, and the most powerful way that you, as an individual, can say “no” to animal exploitation.

Last sentences was a quote from Law professor Gary Francione, who also has written this excellent article: http://articles.philly.com/2009-08-14/news/24986151_1_atlanta-falcons-quarterback-vick-illegal-dog-dog-fights