my mom doesn't know how to grep someone's account. My mom does know how to type her sister's email address into a form.
There's seven billion people in the world for which running grep is not easy. This makes it easy.
And anyone could do the same. It would probably take me the afternoon to create a service that searches an email address in some text files. Overall having people be aware of data leaks is more important than attempting to hide already public data.