No intention to be rude, but do you have proof on this? I'm not arguing one way or another, a well supplemented and gutloaded veiled likely has nothing to worry about at all. At the same time we see a fair amount of mbd cases in veileds. This is probably due to bad husbandry, but something to think about. Seems like every month we are learning new things in this hobby, so questioning the effect of eating large amounts of oxalates(they have enough to cause irritation in dogs/cats/people..) is a good question. I doubt we'll have an answer though.
OP I would just let it go, as long as everything else is right your veiled will live a healthy life.