I don’t know about you, but at the age when we were all taught sex ed in school, I was way too young to understand most of what they were talking about.
It’s hard to absorb information about a topic when you have zero real-life experience with it. Additionally, the curriculum I was taught seems very "bare bones" now that I look back on it. Our experience of sex is about so much more than the necessities, especially when it comes to pleasure.