Obviously, it is a special treatment for girls who are not dignified. There is no necessary connection between short skirts and academic qualifications, and there is no enlightenment when traveling back to ancient times. Wearing short skirts is a fashion expression, not immoral, but the school over-interprets the particularity of girls' wearing.
The school is too lenient. Short skirts and shorts prohibit students' freedom and independence. Schools should not interfere. It's a bit of a violation of girls' rights and interests. I think giving girls the right to wear shorts freely is the best respect for girls.