Even by the standards of today’s political culture, it was a startling image: the talking trains from the children’s television show “Thomas & Friends,” wearing Ku Klux Klan hoods.

That was what viewers of the National Rifle Association’s online video channel saw as Dana Loesch, a spokeswoman for the gun rights group, took the show to task for diversifying its cast.

“They’ve decided that the next stop is Virtue Town,” Ms. Loesch said Friday on “Relentless,” the NRATV program that she hosts. She was responding to news that the children’s show was adding several female and international characters.