Do you think TV shows and made for TV movies that have diverse casts helps to combat racism?

I really had a hard time wording this question.

I was noticing that a lot of the sickening sweet, sappy, TV series and Christmas movies on Hallmark channel and other family channels almost always have at least some diversity, some more than others.

In the past there were shows like Little House and Dr. Quinn that tried to promote understanding and acceptance of other races and cultures. They showed how everyone basically wants the same things, but also pointed out differences in cultures, and showed some ugliness from racist and bigoted characters.

Do you think these shows have a positive affect? Do we need more wholesome shows like these? Are shows with open discussion about race like All In The Family more effective? What about the show Blackish? Or, is it better to barely acknowledge race or ethnicity at all, and just have everyone interact as though the diversity is a complete nonissue? Are shows with predominantly minority casts effective, or is a diverse cast better to decrease racism?