> Misbehaving children need to dealt with too, within the bounds of what is allowed by law. Otherwise, what, you want a loophole for them to get away with all of the above?
None of these establish heckling as illegal. The first two are about the police not being able to arrest the target of the heckling for incitement (which, yeah, clear 1st amendment violation), the last is about Stanford imposing limits, which is entirely different from the government doing so.
https://en.wikipedia.org/wiki/Heckler%27s_veto