Arsenic in fruit juices isn't really all that surprising given that many fruits (principally apple and pears) have arsenic in their seeds. Even fruits that don't may use apple juice as a bulker or have some from cross-contamination in factories, that way.
Do you mean that you don't believe heavy metals can cause brain damage, cancer, etc.? Lead itself makes people stupid and violent, they used to put it in paint and even gasoline. Don't remember that? That's why they call it "unleaded".
Or do you mean that you don't understand why an organization is trying to test juice products for safety? Is it because you trust the people selling the products to produce safe products? That's like self-regulation, man, and self-regulated industries are the dirtiest ever. CR is trying to keep folks honest.
Or did you just read the headline and not the article?
As a father who gives juice to his kids maybe once / week, this is useful information.
