Therapeutic measures

In Denmark there is a system of renting clinics by the hour, and I have been doing so for the past year.
There were a few incidents in the past with  a woman peeing on the toilet seat of cooking and eating in one of the rooms, or some therapist  barking "don't talk to me" when I said hello, but in general, there is a good cohabitation and I do not mind switching off forgotten lights and replacing toilet paper when others do not think of it.
One of the biggest issues is when one of the other therapists do not give a flying fuck about others and speak loudly in the hallways or do not remind their clients to keep it down.
I have been forced many times to remind them with a smile and that has not made me very popular but my priority is with my client and not to be liked.
But a few days ago, a man walked in with a client and they were really loud. The kind of loud that you hear in drunk people ( not saying they were, just creating an analogy). The guy got all twisted in his panties and got really defensive, shouting even more to my face. I was shocked, this is a therapist?
I went to the kitchen and he came in there, itching to continue. He started yelling that this is not a library, and if I dont like it I should not work there, pointing his finger at me. 
I asked him to not point it and he  flipped it and left the room as I managed to say "what an asshole".
I was a bit shaken, I am no stranger to conflict, and I have stood my ground to abuse before, whether it is physical or emotional, and this guy scared me.

I called the owner of the clinic to inform him. I did not have to do that. I felt he should know.

Yesterday I got a mail from him saying the other guy complained I called him an asshole, and that I "insulted " him  in front of his client. The mail went on asking me about unwashed dishes  and that some other therapist complained about it , and "was he lying too?"

I was apalled. First off I did not like the fact I was put in a position to answer and defend myself that way , as if I was a child, to the owner of a clinic, who clearly had his mind set on who was in the wrong. Secondly, dishes or not, it was irrelevant with the fact I was verbally abused and frightened. I informed him a therapist was abusive, he took sides and was accusative, sarcastic and inappropriate.
The owner of that clinic had been unpleasant in the past and has  had a lot of unreasonnable demands ( to pay even when I dont use the clinic , during holidays, as if it was an abonnement), but to blantantly disrespect a situation by mixing things, became too personal .

Bottom line, I think he deserves that therapist, and I am on the lookout for a new  professional "home"