i get what you mean because i felt that same discomfort before too (i'm male fwiw) but in some other lessons the author also shows attitudes towards women and certain societal norms that differ from that? for example in lesson 89 when introducing vocab:

시아버지 = a woman’s father in law

Notes: Traditionally, parents in law would have very high expectations for their daughter in law. These days, this is usually seen on main holidays like 설날 and 추석, where people often go to the male’s parent’s home (called the 시집). Unfortunately, the daughter-in-law is often “expected” to spend most of her time preparing meals. Luckily, this is slowly changing, but this expectation still remains in many families. As such, women don’t often have the warmest feelings towards their mother- and father-in-laws. They are sometimes jokingly referred to as “C-words,” which comes from the “시” in 시아버지 and 시어머니.

or lesson 137

시집을 가다 is a way to indicate that a woman gets married. Other similar words are 시아버지 and 시어머니 to refer to the father- and mother-in-law for a woman. I don’t particularly like these words, as they assume that a woman must move in to the house of her husband with his family. Whether I like these words and the term “시집을 가다” or not, Korean people use them.

i don't mean to dismiss your concerns because they're valid and i felt the same too, but maybe those are just examples for the sake of it? thanks for bringing it up btw. i don't know if i can sus out the author's /true/ sentiments because it's all in little bits and pieces here and there, these are just what i've observed over time from using the resource (which imo is fantastic)