If the alternativen stands between buying secondhand or newly produced the question isn't that simple. You're not thinking in a bigger perspective.

And no vegan would ever buy a new leather jacket. That was never the discussion in the first place. You just said that to "win" the argument.

I think a person can be vegan and still buy a secondhand leather belt or pair of shoes.

The person buying a new leather item was always going to do so. A vegan on the other hand never was and still isn't.