Ground vs. Zapdos

Ground does not equal rock.

Ground gets resisted by Zapdos while Rock is super effective.

does he know rock throw? NO!

Survives, but not a winning option

To explain a bit, Ground is SE against electric but double resisted by flying, for a net single resist.

??‍♂️

Ground has a type advantage over electric so I can understand your initial confusion however Zapdos is also Flying type and that's why it resists ground