I don’t believe this get-together had much to do with Trump at all; RFK’s choice of a leftist has made it clear which candidate is worst impacted by his entry into the race.
These three were getting together to get the message out: Biden is the Democratic Party candidate, and all deviants, blacks, even segregationists like Biden should take note and support him.
They are afraid that RFK Jr. will do for Trump what Ross Perot did for Slick Willy.