"What evidence do you have that they're not?" He shot back almost immediately. It was the same question just on the other end. "Have you thought to ask your brother? Ernie Macmillan? Or any of the others if what I said was true?" So, he was playing a little defensive, but that was how he generally worked.
However, he held up his hand opting to give Percy Weasley something on the off chance he might actually be a reasonable person. "I know they are active because in haste a message to cancel a meeting was not appropriately warded." There was also that Justin's attempts to cover it up where quite pathetic, which for Zacharias only proved his instinct right.