To be entirely clear, Janet being a female was a decision made to benefit all sexes, as many women are raised to be wary of men and thus are often less comfortable around them. While this is also true because of human misogyny, making a male Janet would not be an appropriate solution.
Furthermore, each individual's Good Place neighborhood is designed to fit their needs and desires, as well as those of others with similar needs and desires. You would not experience prejudice of any kind there.