Dear TSA, San Francisco Airport police, and Virgin American staff:
You could not have handled that difficult situation any better. That passenger was behaving irrationally, disturbing those around him, and refusing to move from a seat that was not assigned to him. You did not escalate the situation. You were empathetic and patient (for nearly an hour) as he declined your offers and requests to ameliorate the situation.
We understand that you physically removed him from the plane because you were out of options. He was fighting and screaming, but you maintained focus and did what had to be done. Your job is already difficult. When someone made things impossible, you tried to work with him anyway.
After the fact, the airline staff refused to say anything judgmental about the man. They explained that it might have been medication or his mental state at that time. The pilot even gave all remaining passengers the option to exit the plane after such an upsetting scene. None of us deboarded because we were impressed by your competence and professionalism.