You forgot about the fat-shaming!

Seriously, though, Baron Harkonnen is just the dark reflection of Leto Atreides. The Duke sees his birthright as a matter of responsibility, honour and service to his people. The Baron sees it as having power, using it for self-gratification, and grabbing more. Leto is tall, athletic, wears uniform, regrets not marrying Jessica and is faithful to her. Harkonnen is pomaded and bejewelled, so fat he can't walk without his suspensors, and an abuser of boys. In just the same way, Feyd-Rautha is a negative image of Paul, gleefully murdering slave gladiators while Paul hesitates over killing Jamis in their duel.

Now I dare say whatever conscious or unconscious biases Herbert may have had will have worked their way into the construction of the characters. However, they are secondary, or incidental, to the effect he was trying to achieve.