I would agree about eugenicist, that one requires some understanding about heritability.
But for racism (or similar prejudices based on gender, sexuality, etc), my personal experience, with my own children, indicate that the tendency to group and judge people by their appearance is something that kids to automatically around age 2-3, and that they have to learn to stop. (Kind of like they automatically learn to lie and fight, and have to learn to stop doing that)
And since my children are girls with brown skin in an environment where more than half the kids are white, they focus(ed) a lot on their own skin color, and how that makes people different, just as they do about gender and gender expression. Simply by living in the world, they pick up gender and gender expression. If they see violations of gender-typical behaviour or expression, their first reaction is negative, and they have to be told that it is ok for a boy to hit a boy.
As for the racism part, luckily I have only seen mild expressions of that beyond the basic tendency to use skin color to categorize people. There was maybe one occurance a few years back with my oldest daughter, which made me sit down with her and explain what racism is and why it is not ok. (When she understood that racism could be used against her mother and herself, this was pretty easy)
I think if you travel a bit around the world, especially outside of Europe and the Americas. If you go small towns and villages in Africa, India, South-East Asia, China, Korea and Japan. If you get to know the locals there, not as a tourist, but on a more personal level, you will find that in most places, some kind of racist thinking exists almost everywhere.
If you travel with a person of a different race from yours, it will become extra obvious. Lets say that one of you is white, one is black, asians are likely to treat you quite differently. In some places, there is strong prejudice against Indian people, in some place prejudice agasint Chinese people, etc.
Now if one of you is openly gay or transsexual, the experience would be even mor extreme, an might turn dangerous in some places. In other places (like Thailand) a transsexual person might receive even less attention than in the most progressive places in the US, though. (In Thailand, it is so normal to be a trans-woman, that coming out of the closet is not seen as an achievement. So even the positive feedback that a trans person might get around progressives in the West would be gone. The thais would just instantly accept that the trans woman is socially a woman.)
Oh, and if you think that all those slightly racist or sexist african or asian people are evil people just because of the racism or sexism, maybe you need to look in the mirror.
They simply live in a place that has never had the kind of inclusivity movement that western countries have had after WW2. They are not evil, they simply live in a culture* where some kinds of prejudice is still the norm. Get to know them, and you will find that many of them are still good people with good intentions and kind hearts.
* Not saying that all asians are the same, I mean if you do end up in some village somewhere where the local culture tolerates or even encourages racism or sexism, that village's culture is what I refer to.