Why does Atticus treat his kids like young adults in to kill a mockingbird?

Atticus is a character where he treats everyone equally no matter their race, it is similar in the way he treats his children. He thinks of them as equal. He even tells Uncle Jack that, "When a child asks you something, answer him, for goodness sake... Children are children but they spot an evasion faster than adults, and evasion simply muddles 'em," (61). (page number depends on your copy).