And yet drive through restaurant cashiers are able to interact with drivers daily. And toll booth operators as well. The biggest danger from writing a ticket on the side of the road is other vehicles. Police have the discretion of when to escalate a situation. For example, when to attempt an arrest- They can call for backup or wait until the situation can be safely resolved.
If police need to go to therapy and then they should. If they cannot do their job without suffering from trauma then they should resign.