Just by riding, you are being more free than those poor children trapped in a big yellow cage. They are living a fairly frustrating part of their little lives, being herded to school, being herded around school, and being herded home.
When they see you, they realize that they are jealous of the freedom you have to ride. Being young, the only way they know how to vent that jealousy is to taunt you. (I've actually had adults do this, too).
8% ... sounds like a tough climb, especially on a daily basis when you have cumulative fatigue. I hate hills and I bike an extra 2 miles to avoid one long hill which is less than 8%. So kudos to you for that grind.