I am betting more people know how microwaves work in broad strokes than the kinds of radiation used to sterilize food. I know in the early days of microwave ovens there were a LOT of people who had no idea how it worked and thought if you opened the door too soon deadly radiation would leak out like the ending of Raiders of the Lost Ark and melt everyone's faces. Most kids who grew up in those times understood our parent's concerns were overblown as we all tried microwaving various things for fun.

I think despite the other things our modern society is stupid about, most people get that microwaves are radio waves, because of the prevalence of microwave towers and personal satellite dishes that use microwaves. Meanwhile, barely anyone has any idea what goes on between the carrot fields and walmart grocery bins.