I don't. And I don't need to. What I do know is that it brings unnecessary suffering and that that is wrong. Cultural tradition is not an excuse for cruelty. That is something we recognized in this country when we made the long-standing cultural traditions of dogfighting and cockfighting criminal offenses.
Also, I do not buy meat from a grocery store. The only meat I consume comes from the animals that I raise and humanely slaughter myself. I am careful about the animal products that I buy as well, opting at least for a trusted local source when vegan options are not available.
We will never end cruelty, but that is no excuse for not trying. Abuse of any living thing- from a fighting bull to an elderly human being- is unacceptable and immoral. This is without exception.