Why does President Trump keep attacking MSNBC's Ali Velshi at campaign rallies?

The New York Times

Trump has brought up that Velshi suffered an injury from police while covering the George Floyd protests in May in campaign rallies in Minnesota on Friday, North Carolina on Saturday and Pennsylvania on Tuesday. Although at Tuesday's rally, Trump incorrectly referred to Velshi as “that idiot reporter from CNN." On Saturday, MSNBC called out Trump for saying Velshi's injury was a "beautiful sight." "Freedom of the press is a pillar of our democracy. When the president mocks a journalist for the injury he sustained while putting himself in harm’s way to inform the public, he endangers thousands of other journalists and undermines our freedoms," MSNBC said in a statement.