Because they don’t understand it, and fearing something is much easier to do than to take second semester physics.
It’s not second semester physics, though. It’s like middle school nature & science class. It’s part of understanding the base foundations of our modern world.
Not to mention, we’ve known about and actively used electromagnetic waves since the invention of radio (if we ignore light bulbs and visible light, of course)
Eh, I kind of feel like they tell you about these things in middle school, but you won’t actually understand them well until you take E&M. Up until that point, you’re kind of just accepting what you’ve been told and haven’t been provided in depth knowledge of the subject. Compared to understanding why radiation is ionizing vs non-ionizing, how it behaves, interference, etc.