Consequence of “general education”. School is only 6 hours per day. Reading, math, science, history, and gym are all required. That’s 5. Want to add health, sex ed, art, music, foreign language, programming, speech and debate, driver’s ed? The more you add, the more you have to shorten the classes. My school had a lot of curricular options, so my classes were short. If a school has less to offer, they may have longer classes.