The thing is that everyone gets to make their own call in this kind of situation. If you feel comfortable handling someone who pounds walls or tables at times and you don't feel threatened or intimidated--good for you. If not, feel free to have the person escorted away by security and not see them again. Your threshold for difficult behaviours is enough. I don't think we can judge each other on this one and research notwithstanding I don't think there's always an objective way to know when a tantrum is likely to lead to violence.

We each bring a different history, temperament, physical presence and skill set to interactions with angry and aggressive individuals. That's important.

I am a big believer in the gut feeling, the sense of threat or danger that can be hard to define or quantify. Sometimes I'm with a person who is acting out and I know I'm safe, other times much subtler behaviours make me want to put a lot of distance between us and avoid future interaction. Listening to those feelings has generally stood me in good stead. The OP's therapist was well within her rights to terminate (but retains the duty to refer) even if another therapist facing the same behaviour may have simply said "You're upset. Tell me about your anger."