<<If came into your house and subjected to you to a barrage of questions and refused to stop when you asked me to, do you think you have the right to have me arrested? Or does my freedom of speech mean I can go anywhere and say anything?>>
If I were sponsoring a public lecture in my house and had invited the public to hear it, the situation could well be more complex than you pretend. There is not doubt that when the public lecture came to an end, and the speaker and audience departed, I would have the right to have you ejected if you did not leave voluntarily. However, prior to that moment, I think there's a gray area. Maybe if you had put up warnings to the public, "Free speech can NOT be exercised on my premises, it must stop when I or the management says it must stop," you would be on stronger grounds. But then, who would put up such signs in the first place? It is like inviting people to a lecture but telling them, Sit Down, Shut Up and No Questions Except What We Permit." Few members of the general public would be attracted to such a gathering. Implicitly, I think, the nature of the event gave rise to an assumption that one would be allowed to question, and even to heckle.
However I think you are on even weaker ground because this was an academic institution and not a private residence. Also, I believe the guy that was tasered was a student at that institution.