The cautionary statement was intended for Gunsmoke which was about to start.
Then it makes even less sense than for “Bonanza”. “Gunsmoke” was always sympathetic towards Indians. How many times was Quint a target of prejudice? It was also always sympathetic toward other ethnic types who might show up in Dodge. The depiction of women was fairly realistic for how Old West women lived. (But it provided a highly-sanitized view of what saloon girls were about.) If the warning has to do with the level of violence acceptable in 1960s TV, the violence depicted is nowhere near as graphic as what you are likely to see in the average Lifetime movie.