Doing something routinely and openly that is an unenforced federal felony is to voluntarily surrender your constitutional rights under the 1st, 2nd, 4th, and probably others. (Breaking the law openly like this means they can instantly jail you for speech, for protesting, for being inconvenient, for carrying, and obtain a search warrant at any time.)
It is not "effectively legal", any more than driving 9mph over the limit is. It's just not enforced: it's still a huge felony.