On October 21, J.D. Vance mentioned Robert F. Kennedy, Jr., and also mentioned Jill Stein, while speaking in Wisconsin. See this story. He did not offer any criticism of Democratic efforts to remove Stein from the ballot. He did criticize Democrats for fighting to keep Kennedy on the ballot, something Democrats did in only three states (Wisconsin, Michigan, and North Carolina).
He also said that Kennedy would get more votes than Stein, and said Democrats are forcing Kennedy to be a “spoiler”.