The Royals have banned fraternization with opponents during the game, and Craig Calcaterra puts two and two together:
Maybe there’s more to this story than meets the eye, but what’s meeting the eye here seems pretty dumb: Royals announcer Rex Hudler has made it his personal mission to stop Royals players from being friendly with opposing players during games, so Ned Yost has put a stop to it.
Notably, this is not the first time Rex Hudler has seen the integrity of competition threatened by socialization. This is from 1992:
Rex Hudler, so far as I can tell from personal experiences, is a peach in real life, but I've never been wearing the opposing team's colors, either.