In the U.S. in the 1970s and 1980s, there were different attempts to be gender neutral. One attempt was to use "he/she" and another was to alternate between "he" and "she." Examples: #1 Each student must attend class and complete the course work. He/she can miss one week of classes without penalty. He/she can miss one assignment without penalty. #2 Each student must attend class and complete the course work. He can miss one week of classes without penalty. She can miss one assignment without penalty. These approaches were never broadly accepted. Today, plurals are commonly used. #3 Students must attend class and complete the course work. They can miss one week of classes without penalty. They can miss one assignment without penalty. Singular "they" has become more common. #4 Each student must attend class and complete the course work. They can miss one week of classes without penalty. They can miss one assignment without penalty. "They" has a long history over a few hundred years of being used as a singular pronoun. Here is a BBC article about singular "they." https://public.oed.com/blog/a-brief-history-of-singular-they/

Interesting. Might just be a feminist making a point. Have not seen it before, but .....