Actually, the first rule of Wicca is, indeed, "If it harms no one, then do as you Will."
Also, we have to keep in mind that although this is a public venue, we are within the welcoming, and I might add, safe space of a Wicca subsection of this public venue.
I have heard that some Covens still regard secrecy as a tenant, however, that is for the protection of the members of the Coven, while in an unsafe environment, that was primarily a result of atrocities such as the Salem Witch Trials and the Burning Times during medieval Europe.
To add, Wicca is often referred to as The Craft of the Wise, because in order to really benefit from its practice, you must have an open mind, have an working knowledge of how to think critically, and form your own opinions and make ethical decisions. We don't have a single Book that tells us what's right from what's wrong, we must use our own discernment, and as a result of practicing our beliefs system, we compile our own book to be passed down to other trusted individuals or even groups.