Kinda seems more likely there were just more frogs one year. That happens in nature from time to time.

I don't know. The Egyptions must have been somewhat impressed to let millions of laborers wander off.

Ya know it turns out ol crazy Ramses from down apothecaries way was actually not so crazy

Religion makes people think and do stupid things

Frogs burrow and eat a lot of stuff that benefits plants, like pollinators or other pest control critters.

They will leave your garden barren of life and full of holes and when they pass it will be a vacuum for nature to fill with pests and whatnot.

Add on that frogs are delicious for bigger things that are even scarier for humans, snakes and crocodiles and things.

Also a plague of frogs is probably eating another plague of bugs or something which is also damaging the crops.

Frogs are more of a “pestilence bringer” than a plague unto themselves.

They make a lot of noise and people can't sleep at night, leading to general societal collapse.