"It's an unfortunate incident, and we continue to work with Jose about staying focused on the field," Moore said.
The incident occurred after the fourth inning on Tuesday night after Guillen flied out to end the frame. He and the fan got into it behind first base until coach Luis Silverio and Royals teammates intervened and got Guillen headed to his right-field position.
"It's an ongoing educational process with Jose and what we expect here in Kansas City," Moore said. "I've talked to him many times. It's important to stay focused on what we need to do on the baseball field and manage failure or manage unfilled expectations in a different way."
The fan was relocated to a seat on the left-field side of the stadium after the incident.
"It doesn't matter what a fan says -- you've got to respond in a way that's professional and the best response is no response, most of the time," Moore said.
"The fans have a right to say and act in any way they see fit as long as they don't infringe on the rights of their fellow fans and disrupt their enjoyment of the game."
Manager Trey Hillman missed the whole thing.
"I was actually in the toilet so I didn't see it," he said. "Managers do have to use the restroom so I picked a bad time. I found out about it a half-inning later and we talked about it briefly and there's no sense commenting on it."
Dick Kaegel is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.