A couple points of law and reality. The guy needed to be arrested and charged but not on gun charges but public nuisance, disturbing the peace, menacing or such. I think you have to consider Baker Acting him.

Supreme Court, by so roundly reading the language of one small, anachronistic part of the Constitution — that Second Amendment

Not so the courts have ruled that his behavior is not protected by the Constitution. Laws that prohibit open carry are common.

The constitution does not protect assault weapons either.

Don't go blaming SCOTUS.